The most common payroll mistakes small businesses make in 2026 are late federal tax deposits, overtime calculated on the wrong rate, salaried staff wrongly treated as exempt, workers paid as contractors who are legally employees, and missing the new Form W-2 reporting for qualified overtime. Most of them can be prevented with a deposit calendar and a second review before each payroll is approved.
This guide walks through those common payroll mistakes one at a time, explains the 2026 rules behind each one, and shows a worked overtime example you can use to test your own payroll software.
Payroll errors fall into two groups. Some underpay employees and create wage claims under the Fair Labor Standards Act (FLSA) or state law. Others underpay or misreport federal and state taxes and create IRS penalties. A single error can do both: a worker paid as a contractor, for example, misses overtime and also has no withholding.
Two changes make 2026 a harder year. The One Big Beautiful Bill Act (P.L. 119-21) created a federal income tax deduction for qualified overtime and qualified tips, and employers now carry the reporting load for it. The IRS also updated its core figures for the year. If your software or spreadsheet still uses 2025 numbers, its wage caps and withholding calculations are out of date.
Before reviewing individual mistakes, confirm your payroll setup uses the 2026 figures below. All of them come from IRS Publication 15 (2026), the Employer's Tax Guide.
| Item | 2026 figure |
|---|---|
| Social Security tax rate | 6.2% each for employer and employee |
| Social Security wage base | $184,500 |
| Medicare tax rate | 1.45% each for employer and employee, no wage cap |
| Additional Medicare Tax withholding | 0.9% on an employee's wages above $200,000 in the calendar year |
| FUTA tax rate and wage base | 6.0% on the first $7,000 of each employee's wages |
| Supplemental wage withholding (flat rate) | 22%, rising to 37% on supplemental wages above $1 million |
| Monthly deposit schedule threshold | $50,000 or less of taxes in the lookback period |
| Next-day deposit trigger | $100,000 or more accumulated on any day |
The FUTA rate shown is before the credit for state unemployment tax, and some states have a credit reduction. Our guide to how Form 940 reports federal unemployment tax covers that calculation. For bonuses and commissions, the rules on supplemental wage withholding and the 22% rate explain when the flat rate can be used.
Withheld income tax and both shares of Social Security and Medicare must be deposited on a set schedule. Publication 15 states that if you reported $50,000 or less of taxes for the lookback period, you are a monthly schedule depositor, and monthly depositors must deposit employment taxes on payments made during a month by the 15th day of the following month. Larger employers deposit semiweekly. Any employer that accumulates $100,000 or more in taxes on a single day must deposit by the next business day. All federal tax deposits must be made by electronic funds transfer.
The penalty grows with the number of days late. According to the IRS Failure to Deposit Penalty page, the rates do not add up; each tier replaces the one before it.
| Days late | Penalty rate | Penalty on an $8,000 deposit |
|---|---|---|
| 1 to 5 calendar days | 2% | $160 |
| 6 to 15 calendar days | 5% | $400 |
| More than 15 calendar days | 10% | $800 |
| More than 10 days after the first IRS notice | 15% | $1,200 |
The more serious risk sits behind the deposit. Withheld income tax and the employee share of FICA are trust fund taxes, and Publication 15 notes that the trust fund recovery penalty is 100% of the unpaid trust fund tax. It can be assessed personally against any responsible person who acted willfully, including an officer, an employee or anyone who signs checks for the business. Our explainer on the trust fund recovery penalty and personal liability covers who the IRS can hold responsible.
Prevention: Determine your deposit schedule each year from the lookback period, put every deposit date on a shared calendar, and confirm that your payroll provider is enrolled to make deposits for you. Reconcile deposits to payroll registers every month.
Form 941 is due by April 30, July 31, October 31 and January 31 for the preceding quarter. Totals on the four Forms 941 should tie to Form W-3 and the Forms W-2 at year end. When they do not, the IRS or the Social Security Administration may contact you to reconcile the difference.
For 2026 wages, Forms W-2 must be furnished to employees and filed with the SSA by February 1, 2027, according to the 2026 General Instructions for Forms W-2 and W-3. Line-by-line guidance on the employer's quarterly federal tax return, Form 941 will help you reconcile each quarter before filing.
Prevention: Reconcile the payroll register to the general ledger and to Form 941 every quarter, and keep the reconciliation file. Fix differences in the quarter they arise instead of at year end.
Paying someone a salary does not by itself exempt them from overtime. Under the FLSA, an executive, administrative or professional employee must pass a duties test and a salary test. The Department of Labor's Fact Sheet 17A sets the federal salary test as pay on a salary basis at not less than $684 per week and states plainly that job titles do not determine exempt status. That $684 figure is the current federal level. A Department of Labor final rule published in the Federal Register as document 2026-09839, effective May 15, 2026, removed the vacated 2024 rule text and restored the 2019 levels of $684 per week and $107,432 a year for highly compensated employees.
State law can set a higher salary threshold than the federal one, and where state law is more generous to employees, the employer must follow it. A role that qualifies as exempt in one state may be nonexempt in another, which matters for businesses with remote staff. The overview of multi-state payroll and differing state laws explains how to track those differences.
Prevention: List every salaried role, record which exemption it relies on, and check both the duties and the salary against federal and state tests each January. Reclassify borderline roles before a wage claim forces the decision.
Nonexempt employees must be paid at least one and one-half times their regular rate for hours over 40 in a workweek. The regular rate is often higher than the hourly rate, because it includes all remuneration for employment except payments the FLSA specifically excludes. Department of Labor guidance states that nondiscretionary bonuses are included in the regular rate, and production or attendance bonuses promised in advance usually qualify. The IRS qualified overtime FAQs (FS-2026-13) use the same rule: hours over 40, times one-half, times the FLSA regular rate.
An employee earns $24 per hour, works 46 hours in one workweek and earns a $60 production bonus for that week.
| Step | Calculation | Amount |
|---|---|---|
| Straight-time pay plus bonus | ($24 x 46) + $60 | $1,164.00 |
| Regular rate | $1,164 / 46 hours | $25.30 per hour |
| Overtime premium | 0.5 x $25.30 x 6 overtime hours | $75.91 |
| Correct gross pay | $1,164.00 + $75.91 | $1,239.91 |
| Gross pay if bonus is left out of the rate | ($24 x 40) + ($36 x 6) + $60 | $1,236.00 |
| Underpayment for the week | $1,239.91 minus $1,236.00 | $3.91 |
The premium uses the unrounded regular rate of $25.3043. A $3.91 shortfall looks trivial, yet across 10 employees for 50 weeks it becomes $1,955 in back wages, before any liquidated damages a court may award.
The same calculation now feeds a tax form. Starting with tax year 2026, employers report qualified overtime compensation in Form W-2, box 12, code TT, and the qualifying amount is the premium portion of time-and-a-half pay. In this example, that is the $75.91 premium. If the payroll system computes the premium on the wrong rate, both the paycheck and the W-2 are wrong.
Prevention: Run a test payroll with a bonus and overtime in the same week, and compare the result to a manual calculation like the one above. Confirm with your provider that the system tracks the overtime premium in its own earnings code.
The 2026 Form W-2 instructions add new box 12, code TT, which will be used to report the total amount of qualified overtime compensation, and new box 12, code TP, for the total amount of cash tips reported to the employer. Tipped employers also report the Treasury Tipped Occupation Code in new box 14b. Publication 15 notes that the employee's overtime deduction is capped at $12,500 ($25,000 for married filing jointly), but the employer reports the total qualified amount paid, whatever the employee can deduct.
Qualified overtime is still subject to federal income tax withholding, Social Security tax and federal unemployment tax. The IRS FAQs state that an employer may not reduce withholding for the deduction unless the employee furnishes an updated and valid Form W-4. If code TT is wrong, the employer must file and furnish Form W-2c as soon as possible, and no reporting relief applies for years after 2025. The walkthrough of the 2026 Form W-2 redesign, box 12 codes and box 14b shows where each new amount goes.
Prevention: Set up separate earnings codes for overtime premium and for cash tips now, so the year-end totals are available without reconstructing them from timesheets in January.
The IRS states that if you classify an employee as an independent contractor with no reasonable basis for doing so, you may be held liable for employment taxes for that worker. The FLSA consequences follow too, including unpaid overtime. When status is unclear, either party can file Form SS-8 and the IRS will officially determine the worker's status. Businesses that want to correct the classification going forward can apply to the Voluntary Classification Settlement Program, which offers partial relief from federal employment taxes. See the IRS page on independent contractor versus employee status for the common law tests.
Our guide to 1099 workers for employers covers the control factors that usually decide the question.
Prevention: Review every recurring 1099 payee once a year against the behavioral, financial and relationship factors. Treat a contractor who works set hours under your direction with your tools as a likely employee.
Publication 15 tells employers to ask each new employee to complete the 2026 Form W-4, and to use an employee's updated Form W-4 when one is submitted. A frequent error is entering the form late, so one or two paychecks go out with the wrong withholding. Another is leaving the old withholding profile active after the employee hands in a new form.
Prevention: Make Form W-4 entry part of the onboarding checklist, set the change effective no later than the start of the first payroll period ending on or after the 30th day after you receive it, and store the signed form with the employee record.
The Department of Labor requires employers to preserve payroll records for at least three years and the records on which wage computations are based, such as time cards, for two years. Publication 15 asks employers to keep all employment tax records for at least four years. Many state laws also specify what a pay statement must show, such as hours worked, rates, gross pay, each deduction and net pay.
Manual adjustments are a common source of undetected errors. Bonuses, retro pay, garnishment changes and one-off deductions are typed in by hand, often under deadline pressure.
Prevention: Have one person enter adjustments and a second person approve them before each payroll is released. For a very small team, this can be the owner reviewing a one-page variance report that compares gross pay per employee to the prior period.
Each check below targets one or more of the mistakes above.
| Review check | Mistake it catches |
|---|---|
| A second reviewer approves manual adjustments and compares gross pay per employee to the prior period | Keying errors and missed or duplicated bonuses (Mistake 8) |
| Match each federal deposit in EFTPS to the payroll register | Late or short deposits (Mistake 1) |
| Tie the payroll register to Form 941 each quarter | Filing mismatches (Mistake 2) |
| Test a week with overtime and a bonus after any software or pay-plan change | Wrong regular rate and wrong code TT totals (Mistakes 4 and 5) |
| Review exempt roles and recurring 1099 payees each January | Exempt and contractor misclassification (Mistakes 3 and 6) |
For the complete list of deposit, filing and year-end deadlines, use our payroll compliance checklist.
What is the most expensive payroll mistake for a small business? Unpaid trust fund taxes often cost the most. The trust fund recovery penalty equals 100% of the unpaid withheld taxes and can be assessed personally against responsible persons who acted willfully, in addition to deposit penalties and interest.
How much is the IRS penalty for a late payroll tax deposit? It is 2% if the deposit is 1 to 5 days late, 5% for 6 to 15 days, 10% after more than 15 days and 15% if the tax is still unpaid more than 10 days after the first IRS notice. The tiers replace each other and do not add together.
Do employers have to report qualified overtime on the 2026 Form W-2? Yes. For tax year 2026, employers report total qualified overtime compensation in box 12 with code TT. The amount is the premium portion of time-and-a-half pay, and it remains subject to income tax withholding and Social Security tax.
How do I fix a payroll mistake after the quarter has closed? Correct the employee's pay first, then file Form 941-X for the affected quarter, and file Form W-2c and Form W-3c with the SSA for any Form W-2 already issued. Keep a written record of how the error was found and fixed.
Madras Accountancy supports small businesses and CPA firms with payroll processing support, deposit and filing calendars, quarterly reconciliations and year-end W-2 and 1099 preparation. If your payroll setup has not been reviewed since the 2026 changes, contact our team to talk through what a review would cover.
The section 4960 excise tax is 21% of nonprofit pay over $1M. From 2026 it covers all employees. See the medical carve-outs, Form 4720 and a worked example.
The paid family and medical leave tax credit is permanent from 2026. See the 12.5% to 25% rates, the premium option, the 6-month rule and how Form 8994 works.
Opportunity zones become permanent in 2027 under the One Big Beautiful Bill. See the new deferral, rural bonus, and the 2026 handoff.
