The US Employer’s Payroll Compliance Handbook (2026)

Payroll compliance in the United States is the employer's obligation to withhold, deposit, report, and document federal, state, and local payroll taxes while also following wage-hour, classification, benefits, and leave rules that affect pay administration. 

For most employers, payroll compliance spans multiple overlapping frameworks: federal tax withholding and deposit rules set by the IRS, wage and hour protections enforced by the Department of Labor, worker classification standards applied by both agencies, state and local tax obligations that vary by jurisdiction, and benefits and leave programs that directly affect how employees are paid. 

This handbook covers the full scope of US employer payroll obligations, explains where compliance most commonly breaks down, and identifies the operational controls that reduce error and support audit readiness. It serves as the hub for the IRIS US Payroll Compliance content cluster, with links to deeper guides on FICA, worker classification, 401(k) administration, and paid family leave throughout. 

Sources: IRS Publication 15 (Circular E); IRS Publication 15-T; DOL FLSA guidance; DOL FMLA regulations; state agency guidance 

What Payroll Compliance Covers 

Core payroll obligations 

Payroll compliance is not a single obligation; it is a recurring set of interconnected responsibilities that must be executed accurately at each pay cycle and reconciled at quarter-end and year-end. The core employer obligations are: 

• Tax withholding: federal income tax withheld from employee wages based on Form W-4 elections and IRS withholding tables; state and local income tax withheld where applicable 
• Tax deposits: timely deposit of withheld employee taxes and employer-matching FICA contributions to the IRS on the correct schedule (monthly or semi-weekly) and to state agencies on their prescribed timelines 
• Wage and hour compliance: paying at least the applicable federal and state minimum wage, calculating overtime correctly for nonexempt employees, and maintaining the records required under the Fair Labor Standards Act 
• Worker classification: correctly distinguishing between W-2 employees and 1099 independent contractors, and applying the corresponding tax treatment, benefits eligibility, and reporting obligations to each 
• Benefits deductions: administering pre-tax and post-tax deductions for health insurance, retirement contributions, flexible spending accounts, and other benefit programs accurately and in the correct order
• Leave-related pay administration: managing pay status changes, benefit deduction continuity, and leave coordination for FMLA, state paid family and medical leave, and other statutory leave programs 
• Recordkeeping and reporting: completing quarterly and annual IRS filings, issuing W-2s, maintaining records for the required retention period, and producing documentation that supports IRS, DOL, and state agency audits 

Who this guide is for 

This handbook is written for payroll managers, HR directors, finance leaders, controllers, and business owners who are operationally responsible for payroll accuracy, tax deposit compliance, and workforce reporting. It assumes familiarity with basic payroll and tax concepts and focuses on compliance obligations, risk management, and process control rather than introductory payroll mechanics. 

Navigating Federal Payroll Taxes 

Federal payroll tax obligations apply universally to all US employers with W-2 employees. They are enforced by the IRS, subject to significant penalties for late or incorrect deposits, and must be reconciled quarterly on Form 941 and annually on Form 940. The employer's role is both to withhold from employee wages and to contribute employer-side taxes on top of those wages. 

Federal Income Tax Withholding 

Federal income tax withholding is calculated based on each employee's Form W-4 elections and the IRS withholding method the employer applies. The two primary methods — the Wage Bracket Method and the Percentage Method, both detailed in IRS Publication 15-T — produce the same outcome when applied correctly but differ in their calculation approach. 

Supplemental wages — bonuses, commissions, overtime above regular pay, and back pay — are subject to a flat 22% federal withholding rate for most employees. Where cumulative supplemental wages paid to an employee in the calendar year exceed $1 million, the rate increases to 37%. Payroll systems must distinguish between regular and supplemental wage payments and apply the correct method to each. 

The W-4 form was substantially revised in 2020. Employers with employees who have not submitted a 2020 or later W-4 must continue using the prior withholding method for those employees and cannot require them to update their W-4. Payroll teams processing multiple withholding calculation methods simultaneously are a common source of error in organizations with long-tenured workforces. 

FICA Taxes: Social Security and Medicare 

FICA taxes fund Social Security and Medicare. The employer withholds the employee's share from wages and contributes a matching employer share on top. Social Security is taxed at 6.2% for both employee and employer on wages up to the annual wage base limit. Medicare is taxed at 1.45% for both parties on all wages with no cap. The Additional Medicare Tax of 0.9% applies to employee wages above $200,000 in the calendar year; there is no employer match on this additional amount. 

FICA calculations must account for the cumulative wage base for Social Security, the Additional Medicare Tax trigger, and the interaction between regular wages and supplemental compensation. For employers paying large year-end bonuses or commission draws, the payroll system must apply year-to-date earnings correctly to avoid over or under-withholding. 

Federal Unemployment Tax Act (FUTA) 

FUTA is an employer-only tax; no amount is withheld from employee wages. The FUTA rate is 6% on the first $7,000 of wages paid to each employee in the calendar year. Employers who pay their State Unemployment Insurance (SUI) obligations on time are eligible for a FUTA credit of up to 5.4%, reducing the effective FUTA rate to 0.6% for most employers. 

Credit reduction applies in states that have outstanding federal unemployment loan balances. In credit reduction states, the 5.4% credit is reduced by the applicable credit reduction percentage, increasing the employer's effective FUTA liability. Employers with operations in multiple states must check the annual list of credit reduction states published by the DOL before filing Form 940. 

FUTA is reported and paid annually on Form 940, due January 31. Deposits are required quarterly where the cumulative FUTA liability exceeds $500. 

Federal deposit and filing obligations 

The federal payroll tax deposit schedule — monthly or semi-weekly — is determined by the employer's total tax liability during the lookback period (the 12-month period ending June 30 of the prior year). New employers default to the monthly schedule. Employers whose lookback period tax liability exceeded $50,000 are semi-weekly depositors. 

The semi-weekly schedule requires deposits within three banking days of paydays falling on Wednesday, Thursday, or Friday, and by the following Wednesday for paydays on Saturday through Tuesday. The $100,000 next-day rule requires a deposit by the next business day whenever accumulated liability in a deposit period reaches $100,000 or more, regardless of the employer's normal schedule. 

Quarterly Form 941 filings are due April 30, July 31, October 31, and January 31. The Form 941 must reconcile total wages, withheld taxes, and deposits made during the quarter. Year-end W-2s must be filed with the Social Security Administration and distributed to employees by January 31. 

State and Local Payroll Complexities 

Federal compliance establishes the floor. State and local obligations layer on top of it, often with different wage bases, different deposit schedules, different forms, and different enforcement agencies. For employers with employees in more than one state, managing this complexity is one of the most operationally demanding aspects of payroll administration. 

State income tax withholding 

Forty-one states plus the District of Columbia impose a state income tax requiring employer withholding. The withholding obligation is generally based on where the employee works, not where the employer is headquartered. Remote work has significantly complicated this: an employee who relocates from New York to Florida without notifying their employer changes the employer's withholding obligation immediately, even if the employer's payroll system is still configured for New York. 

Some states impose a resident tax credit that partially offsets the double-withholding exposure for employees who live in one state and work in another. Reciprocity agreements between states allow employees to be taxed only in their home state. Employers must understand the applicable agreements for each employee's state combination and apply them correctly or risk over-withholding, which creates employee relations issues, and under-withholding, which creates employer liability. 

State unemployment insurance 

SUI is an employer-paid tax that funds state unemployment benefits. Every state administers its own SUI program with its own taxable wage base, rate schedule, and reporting requirements. An employer's SUI rate within a state is determined by its experience rating — its historical layoff and benefit charge history. New employers are assigned a standard rate until sufficient experience data is available. 

Employers must register with the SUI agency in every state where they have payroll obligations. Failure to register before the first payroll run in a new state creates registration penalties and retroactive liability for the missed quarters. For employers adding new states due to remote worker moves, the registration obligation arises at the moment the employee begins working in that state, not when HR formally acknowledges the location change. 

Local taxes and surtaxes 

Certain cities, counties, and transit districts impose local payroll taxes that operate independently of state income tax. Major local tax jurisdictions include New York City, Philadelphia, Pittsburgh, Kansas City, St. Louis, and the Kentucky cities. Ohio has more than 600 separate municipal income tax jurisdictions. Some jurisdictions require employer withholding; others are self-assessed by employees. 

Local tax compliance requires identifying the applicable jurisdiction for each employee's work location, registering with the local tax authority, and configuring payroll withholding to apply the correct rate. Payroll software that maintains a current database of local tax rates and jurisdiction rules is a material operational advantage in high-complexity states. 

Multi-state payroll risk 

Distributed workforces create a compliance matrix that grows in complexity with each additional state. A business with employees in ten states has ten separate SUI programs, up to ten state income tax withholding registrations, potentially multiple local tax obligations, and ten sets of state wage and hour rules — each of which may differ from federal standards on minimum wage, overtime, meal breaks, and pay frequency requirements. 

The most common multi-state failure modes are: withholding configured for the employer's home state rather than the employee's work state; SUI not registered in a state where a remote worker has been working for months; and local tax obligations missed because the employer's payroll system does not include the relevant jurisdiction. Each creates retroactive liability from the date the obligation first arose. 

Wage and Hour Compliance 

Wage and hour compliance is enforced by the Department of Labor's Wage and Hour Division and, in many states, by state labor agencies with independent enforcement authority. DOL investigations can result in back wage awards, liquidated damages, civil money penalties, and public disclosure. The payroll team's role is to ensure that pay calculations are correct, that FLSA classifications are applied accurately, and that records are sufficient to defend against a DOL audit. 

Minimum wage and overtime 

The federal minimum wage is $7.25 per hour, unchanged since 2009. Many states and localities have higher minimums; the applicable rate is the highest of the federal, state, and local minimum wages for the employee's work location. Employers must track minimum wage changes by jurisdiction, which occur throughout the year as state laws phase in scheduled increases. 

FLSA overtime applies to nonexempt employees who work more than 40 hours in a workweek. The overtime rate is one and one-half times the employee's regular rate of pay, not their base hourly rate. The regular rate calculation includes most forms of compensation: hourly wages, shift differentials, non-discretionary bonuses, and commissions. It excludes gifts, discretionary bonuses, and certain other payments specifically listed in the FLSA. 

Misapplying the regular rate — for example, calculating overtime on base pay only when the employee also received a productivity bonus during that workweek — systematically underpays overtime and creates retroactive liability for every affected pay period. The DOL's Wage and Hour Division actively enforces regular rate errors, and back wage investigations often cover the full two-year FLSA statute of limitations, or three years for willful violations. 

Worker classification 

Worker classification is one of the highest-risk payroll compliance decisions an employer makes. Misclassifying a W-2 employee as a 1099 independent contractor means the employer has not withheld federal or state income tax, has not paid or matched FICA, has not reported wages on Form W-2, and may have excluded the worker from benefits and leave programs to which they were legally entitled. When the IRS or DOL reclassifies the worker, all of those omissions become back liabilities with penalties and interest. 

The IRS Common Law Rules and the DOL's economic reality test are the primary frameworks for determining worker status. Both focus on the degree of control the business exercises over the work, the worker's economic independence, and the permanence of the relationship. A written agreement that labels someone a contractor does not override the facts of the working relationship. 

Payroll consequences of misclassification 

Beyond the back tax liability, worker misclassification creates downstream consequences across every system and process that depends on classification: the worker should have been included in the 401(k) plan but was not; FMLA protections were not offered; state paid leave premiums were not withheld; overtime was not paid because the worker was not treated as an employee subject to FLSA. Each of these omissions is a separate liability that compounds the original classification error. 

The IRS Section 3509 rates apply to unintentional misclassification where the employer did not file required information returns. In cases of intentional misclassification, the penalty structure escalates significantly. For employers who discover a classification error before an audit, the IRS Voluntary Classification Settlement Program (VCSP) offers reduced penalty exposure in exchange for prospective reclassification. 

Benefits, Deductions, and Leave Administration 

Benefits and leave programs are payroll compliance obligations, not just HR design choices. How deductions are taken, when they must be deposited, how leave pay interacts with benefit continuation, and how different benefit types affect taxable wages all have direct payroll consequences that must be executed correctly at each pay cycle. 

Pre-tax and post-tax deductions 

Pre-tax deductions reduce the employee's gross income for federal income tax purposes before FICA is calculated. Common pre-tax deductions include employee 401(k) salary deferrals, health insurance premiums under a Section 125 cafeteria plan, and flexible spending account contributions. Note that 401(k) salary deferrals are FICA-taxable even though they are income tax-exempt; health insurance premiums under a Section 125 plan reduce both income tax and FICA wages. 

Post-tax deductions are taken from after-tax earnings and do not reduce taxable wages. Roth 401(k) contributions, certain disability insurance premiums, and life insurance above the $50,000 threshold are processed post-tax. The distinction matters because errors in deduction sequencing produce incorrect tax calculations for every affected employee in every affected pay period. 

The order in which deductions are applied — and whether each deduction is taken before or after taxes — must be configured accurately in the payroll system before the first pay run. Deduction sequencing errors that are not caught during setup will replicate across every payroll cycle until they are identified and corrected. 

401(k) payroll administration 

Administering a 401(k) plan through payroll involves more than deducting the employee's deferral election from each paycheck. Employee contributions must be deposited into the plan trust as soon as they can reasonably be segregated from the employer's general assets, with a seven-business-day safe harbor for small plans. Late deposits are a prohibited transaction under ERISA, subject to a 15% excise tax and potential personal fiduciary liability. 

Employer matching contributions must be calculated against the plan's formula at each pay period, applied to the correct compensation definition specified in the plan document, and deposited on the plan's required schedule. Annual non-discrimination testing (ADP/ACP) depends on the payroll system's ability to produce accurate compensation and deferral data by employee and by HCE/NHCE status. 

Leave-related pay administration 

FMLA and state paid family and medical leave programs directly affect payroll in three ways: they change the employee's pay status (from full pay to reduced pay or unpaid status); they trigger or modify benefit deduction obligations (health insurance premiums must be maintained under FMLA; some state programs require ongoing SUI deductions during leave); and they require coordination between the leave tracking system and payroll to ensure the correct gross wages are calculated for each pay period. 

State paid leave programs require employer payroll deductions for employee premiums in most states, and employer contributions in several. As of January 2026, Maryland, Minnesota, and Delaware all launched their state PFML programs, adding new withholding and remittance obligations for employers with employees in those states. Employers who have not yet configured these deductions are currently non-compliant. 

Other payroll deductions and attachments 

Wage garnishments, child support orders, tax levies, student loan garnishments, and creditor garnishments are mandatory payroll deductions that require the employer to divert a portion of the employee's wages to a third party. The employer has no discretion about whether to comply with a properly served order; failure to honor a valid garnishment creates direct liability to the creditor or agency. 

The Consumer Credit Protection Act limits the amount that can be garnished from an employee's disposable earnings: the lesser of 25% of disposable earnings or the amount by which disposable earnings exceed 30 times the federal minimum wage per workweek. Child support orders have higher limits — up to 50 to 65% of disposable earnings depending on the employee's support obligations for other dependents. 

IRS tax levies do not follow the CCPA limits; they use IRS Publication 1494 to calculate the exempt amount based on the employee's filing status and number of dependents. Payroll teams must be trained to identify the order in which multiple attachments are processed when an employee is subject to more than one garnishment simultaneously. 

Recordkeeping and Reporting 

Payroll recordkeeping is a legal obligation, not a discretionary practice. The IRS, DOL, and state agencies all specify minimum retention periods for different categories of payroll records. An employer that cannot produce adequate records during an audit is presumed non-compliant; the burden of disproving the audit findings shifts to the employer. 

Quarterly and annual IRS forms 

Form 941 is the quarterly payroll tax return that reconciles wages paid, taxes withheld, and deposits made during each quarter. Errors on Form 941 — whether from incorrect wage coding, misapplied withholding rates, or deposit timing mismatches — generate IRS notices that require amended filings and, depending on the nature of the error, additional interest and penalty. 

Form 940 is the annual FUTA return. It must reconcile the FUTA tax liability across all four quarters, account for the SUI credit and any credit reduction, and match the FUTA deposits made during the year. W-2s must reconcile with the quarterly 941 totals: the cumulative wages and withholding reported across all four 941s must equal the aggregated W-2 figures reported to the SSA. A reconciliation gap triggers an IRS matching failure and an associated notice. 

Payroll record keeping requirements 

Federal record keeping obligations differ by record type and agency: 

• FLSA payroll records: retained for at least three years from the date the record is made. Includes payroll registers, time cards, work schedules, and pay rate records. 
• FLSA wage computation records: retained for at least two years. Includes time and motion study records, job evaluation records, and merit system records used to set wages. 
• IRS tax records: generally four years from the date the tax is due or paid, whichever is later. Includes employment tax records, W-4 forms, and records supporting the amounts reported on 941 and 940. 
• FMLA records: three years. Includes leave requests, medical certifications, designation notices, and payroll records showing leave taken. 
• ERISA plan records (401(k)): six years for records supporting the Form 5500; four years for participant records. 

The practical challenge is maintaining these records in a way that supports rapid retrieval during an audit. Records that technically exist but are scattered across email threads, shared drives, and local spreadsheets may satisfy the letter of the retention requirement while failing the spirit of audit readiness. 

Audit readiness 

IRS, DOL, and state agency audits typically open with a document request covering specific record types for a defined period. The employer's ability to respond promptly and completely — without reconstruction or approximation — significantly affects both the audit's scope and its outcome. 

Payroll teams that maintain a consistent, system-generated audit trail — showing the gross wage, each withholding component, each deduction, the deposit date, and the Form 941 it was included in — can respond to most IRS correspondence without engaging legal counsel. Teams that reconstruct records from memory or partial data are at a structural disadvantage before the substantive questions are even asked. 

Common Payroll Errors and Risks 

Frequent employer payroll mistakes 

The following errors represent the highest-frequency compliance failures in US employer payroll operations. Each has a predictable cause and a corresponding prevention measure. 

• Incorrect state withholding after a remote work move: employee relocates to a new state; payroll continues to withhold for the previous state. Creates retroactive liability in the new state and potential over-withholding liability in the old state. 
• Worker misclassification: 1099 treatment applied to a worker who meets the IRS or DOL employee tests. Generates back tax, FICA, overtime, and benefits liability compounding from the original misclassification date. 
• Missed deposit deadlines: manual deposit processes that don’t track the deposit schedule or accumulate daily liability miss the $100,000 next-day threshold or the semi-weekly window. Late deposit penalties begin at 2% and escalate to 15%. 
• Incorrect handling of bonuses or supplemental wages: bonuses processed as regular wages instead of supplemental wages, or supplemental wages aggregated with regular pay and withheld at the composite rate rather than the flat 22% supplemental rate. 
• Errors in pre-tax deduction setup: health insurance premiums configured as post-tax, or 401(k) deferrals set up to reduce FICA wages when they should not. Produces systematic under or over-withholding across every affected employee each pay period. 
• Inaccurate leave or benefits coordination: FMLA leave not correctly designated; state PFML deductions not configured; benefit premiums not maintained correctly during leave periods. 
• Late or incorrect year-end reporting: W-2s not reconciling with 941 totals; state W-2 filings missed; corrections not filed on Form W-2c before state and local deadlines. 

Consequences of payroll errors 

Payroll errors do not self-correct. Each missed deposit, each miscalculated withholding, and each incorrect W-2 creates a correction obligation that compounds over time. The typical consequence chain includes: 

• IRS penalties and interest: late deposit penalties of 2% to 15%; failure-to-file penalties on late 941s; accuracy-related penalties on under-reported tax.
• Amended filings: Form 941-X for corrected quarterly returns; Form W-2c for corrected wage statements; Form 843 for penalty abatement requests. 
• Back wages and liquidated damages: DOL investigations resulting in back wage awards for overtime or minimum wage violations, plus an equal amount of liquidated damages. 
• State agency assessments: retroactive SUI liability for unreported wages; state income tax underpayment assessments; state wage and hour penalties that in some jurisdictions exceed federal exposure. 
• Increased administrative burden: correcting a payroll error typically takes three to five times longer than preventing it. A systematic error affecting 50 employees across eight quarters requires individual recalculations, amended filings, employee notifications, and W-2c issuance. 

What Employers Should Watch in 2026 

2026 payroll developments 

Payroll compliance is not static. The following areas require active monitoring by payroll and HR teams in 2026. 

• State paid leave program launches: Maryland, Minnesota, and Delaware all launched mandatory PFML programs effective January 1, 2026, adding new payroll deduction and remittance obligations for employers with employees in those states. Employers who have not yet registered and configured these deductions are retroactively non-compliant from January 1. 
• State minimum wage increases: multiple states scheduled minimum wage increases for 2026. Payroll systems must be updated to apply the new rates from the effective date in each applicable jurisdiction. 
• Multi-state withholding registration: the growth of distributed and remote workforces continues to expand multi-state withholding obligations. Employers should audit their state registrations against their current employee work location data at least quarterly. 
• IRS withholding table updates: the IRS updates Publication 15-T annually. Payroll teams should confirm that their software has applied the current year’s withholding tables before the first January payroll run. 
• Data security and employee identity protection: payroll systems are high-value targets for phishing, data breaches, and fraudulent W-2 requests. The IRS’s annual reminder to payroll and HR teams on W-2 scam prevention reflects the ongoing exposure. Employers should verify their data access controls, multi-factor authentication settings, and W-2 delivery protocols. 
• Tips, overtime, and premium pay tracking: employers in hospitality, food service, and other tip-dependent industries must ensure that tip reporting, tip credit calculations, and tip pooling arrangements comply with current DOL guidance, which has been the subject of regulatory activity in recent years. 

Why 2026 matters 

Payroll compliance obligations change at the federal, state, and local levels throughout the year. States set minimum wage increases that take effect mid-year. New PFML programs launch with premium rates that change annually. IRS thresholds for deposit schedules shift with lookback period recalculations. An employer operating on year-old configuration settings in a multi-state environment will almost certainly be non-compliant on at least one obligation before the year is out. 

The practical response is not to monitor every change in real time — no payroll team has that bandwidth — but to establish a structured review cycle: quarterly checks for state registration completeness, annual verification of withholding table and rate updates, and immediate action when a worker relocates or a new state is entered for the first time. 

Automating Payroll Compliance with IRIS 

The cost of manual payroll 

Managing payroll compliance manually — across spreadsheets, disconnected state portals, manually calculated withholding, and ad hoc year-end reconciliation — creates a compounding administrative burden that grows with every new state, every new employee, and every regulatory change. The cost is not primarily in the software licensing comparison; it is in the hours consumed by reconciliation, the errors introduced by manual data entry, and the risk exposure created by configuration gaps that are not identified until an audit opens. 

For a payroll team managing employees across five states, the manual workload includes: tracking five separate SUI wage bases and rate schedules; maintaining five state withholding registrations; applying five potentially different minimum wage rates; and reconciling five separate state quarterly returns alongside Form 941. When a worker relocates to a sixth state mid-year, the setup and registration process starts from scratch with no systematic prompt to complete it. 

The audit exposure compounds the operational cost. A DOL Wage and Hour investigation covering two years of overtime calculations requires two years of time records, wage computations, and pay stubs to be produced in a structured format. An IRS notice challenging a Form 941 balance requires the quarterly reconciliation to be traceable to individual pay register entries. Manual systems produce this documentation only if someone has consistently maintained it — which, in most manual environments, they have not. 

How IRIS Payroll Software helps 

IRIS Payroll Software is a cloud-based payroll solution designed to support US employers managing federal, state, and local payroll compliance across a distributed workforce. 

IRIS Payroll Software can help reduce manual compliance burden in several specific areas: 

• Federal, state, and local tax calculations: tax tables and withholding rules are maintained within the platform and updated at each regulatory change, helping to reduce the risk that payroll runs on stale rates after a federal, state, or local update. 
• Recurring payroll processing: scheduled payroll workflows with built-in validation reduce the opportunity for manual data entry errors and missed steps. 
• Benefits and deduction management: pre-tax and post-tax deductions configured in the system apply consistently at each pay run, reducing the risk of sequencing errors or missed deduction updates after open enrollment.
• Reporting workflows: Form 941 data, W-2 generation, and state reporting outputs are built from the system’s payroll records rather than manually assembled from separate sources, supporting reconciliation accuracy.
• Multi-state payroll support: state-specific withholding configurations and SUI tracking are maintained within the platform, supporting employers with distributed workforces. 

Commercial bridge 

The business case for payroll automation is not built on software cost alone. It is built on the cost of the errors that manual processes generate, the time consumed correcting them, and the audit exposure that inconsistent records create. A single DOL Wage and Hour investigation covering two years of overtime records costs more in legal fees and management time than a payroll platform investment for most mid-market employers. 

The goal is not a guarantee of compliance — software cannot substitute for correct HR and management decisions, or for the employer's responsibility to register in new states before running payroll there. What well-configured payroll software does is reduce the calculation error rate, apply consistent treatment across jurisdictions, and produce the audit trail that demonstrates that the employer took the compliance obligation seriously. 

Explore IRIS Payroll Software — the payroll solution designed to help US employers manage complex payroll operations with greater consistency and control. 

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US Payroll Compliance: Frequently Asked Questions 

What are the penalties for late payroll tax deposits? 

The IRS imposes tiered penalties on late payroll tax deposits based on how late the deposit is relative to the due date. Deposits made one to five days late incur a 2% penalty. Deposits six to fifteen days late incur a 5% penalty. Deposits more than fifteen days late incur a 10% penalty. Where amounts remain undeposited ten days after the first IRS notice, the penalty increases to 15%. Interest accrues on unpaid amounts from the deposit due date. 

The IRS does provide for first-time penalty abatement for employers with a clean deposit history, and reasonable cause relief may be available in limited circumstances. Penalties should be addressed through Form 843 with supporting documentation. The most effective approach is preventing late deposits through automated deposit scheduling integrated with the payroll cycle, rather than pursuing abatement after the fact. 

How long must employers keep payroll records under the FLSA? 

The FLSA requires employers to retain payroll records for at least three years. This includes payroll registers, time and attendance records, work schedules, pay rate records, and collective bargaining agreements. Wage computation records — including time cards, piecework tickets, and job evaluation records used to set wages — must be retained for at least two years. 

IRS requirements for employment tax records generally impose a four-year retention period from the date the tax was due or paid, whichever is later. ERISA requires plan records supporting Form 5500 to be retained for six years. FMLA records must be retained for three years. Where multiple requirements apply to the same record, the longer retention period governs. Employers should establish a records retention schedule that accounts for the longest applicable requirement for each record category. 

Do employers have to pay out unused PTO when an employee leaves? 

Federal law does not require employers to pay out accrued unused PTO on termination. The obligation depends entirely on state law, the employer's written policy, and any applicable employment agreement. Some states — including California, Colorado, and North Dakota — treat accrued vacation as earned wages that must be paid on termination. Other states treat PTO payout as discretionary, governed by the employer's policy. 

Employers whose policy states that PTO is forfeited on termination may enforce that policy in states that permit it, but cannot enforce it in states that treat accrued PTO as earned wages regardless of policy language. Employers with employees in multiple states must maintain state-specific policies or apply the most generous standard uniformly. Failure to pay out accrued PTO in a state that requires it is an unpaid wage claim, subject to back pay, penalties, and in some states, attorney’s fees. 

What payroll issues create the most risk for employers? 

The highest-risk payroll compliance issues for most US employers are: worker misclassification (which creates retrospective FICA, income tax, overtime, and benefits liability from the date of original misclassification); multi-state withholding errors, particularly for remote workers whose location changes without triggering a payroll reconfiguration; late or missed payroll tax deposits, which accrue penalties and interest from the first day past due; and year-end reporting errors that produce W-2/941 reconciliation mismatches. 

Beneath these, common operational risks include: incorrect regular rate calculations for overtime purposes when employees receive bonuses or shift differentials; pre-tax deduction sequencing errors that systematically miscalculate taxable wages; and new-state registration failures where an employer begins running payroll in a state before completing SUI and income tax withholding registration. Each of these is a recurring, high-frequency issue across employer payroll audits at both the federal and state level.