Commission income is taxed as ordinary income, which means every dollar is subject to federal income tax plus Social Security and Medicare tax. How commissions are taxed in practice, though, depends on whether you receive them as a W-2 employee or as a 1099 independent contractor. Employees have taxes pulled out of the check before it hits their account. Contractors get the gross amount and owe the full bill themselves, including both halves of Social Security and Medicare.
Commissions Paid to W-2 Employees
The IRS treats employee commissions as “supplemental wages,” the same category as bonuses, severance, and back pay.1Internal Revenue Service. Publication 15 – Employer’s Tax Guide That classification gives your employer two ways to calculate federal income tax withholding on a commission check.
The first is the flat rate method. When the commission is paid separately from your regular wages, or is combined but identified as a separate amount, the employer can withhold a flat 22% for federal income tax.1Internal Revenue Service. Publication 15 – Employer’s Tax Guide This applies while your total supplemental wages for the year stay at or below $1 million.
The second is the aggregate method. Your employer adds the commission to your regular wages for the pay period and calculates withholding on the combined total using the standard tables and your W-4. Depending on your salary, this can withhold more or less than a flat 22%, and a large commission stacked on top of a regular paycheck often produces what looks like an outsized tax bite for that period.
Once your supplemental wages exceed $1 million in a calendar year, the rules stop being flexible. Every dollar above $1 million must be withheld at 37%, and your W-4 elections cannot reduce it.1Internal Revenue Service. Publication 15 – Employer’s Tax Guide
Social Security and Medicare on Employee Commissions
FICA comes out of every commission payment the same way it comes out of your regular salary. Social Security is 6.2% of wages up to $184,500 for 2026, matched by your employer.2Social Security Administration. Contribution and Benefit Base Once your total wages hit that cap, Social Security withholding stops for the year. Medicare is 1.45% on all wages with no cap, also matched.
Higher earners pick up an extra layer. If your Medicare wages exceed $200,000 in a calendar year, your employer must withhold an additional 0.9% Medicare tax on wages above that point.3Internal Revenue Service. Questions and Answers for the Additional Medicare Tax The filing-status thresholds you’ll settle up against at year-end are $200,000 for single filers, $250,000 for joint filers, and $125,000 for married filing separately. There is no employer match on the 0.9%. Commission earners hit this more often than salaried workers because a couple of strong quarters can push cumulative wages past the threshold without warning.
Everything reported and everything withheld shows up on your Form W-2 after year-end.
Commissions Paid to 1099 Contractors
Independent contractors receive the full commission with nothing withheld. The paying business reports the total on Form 1099-NEC after year-end, but the tax obligation is entirely yours to calculate and pay.4Internal Revenue Service. Form 1099-NEC and Independent Contractors Two categories of tax apply: regular income tax at your marginal rate, and self-employment tax.
Self-Employment Tax
Self-employment tax covers the Social Security and Medicare contributions that an employer would normally split with you. Because you are both sides of that relationship, you pay both halves: 12.4% for Social Security and 2.9% for Medicare, for a combined 15.3%.5Internal Revenue Service. Topic No. 554, Self-Employment Tax
The tax applies to 92.35% of your net earnings rather than 100%, which mirrors the fact that W-2 employees don’t pay FICA on the employer’s share.5Internal Revenue Service. Topic No. 554, Self-Employment Tax So $100,000 of net commission income after business expenses produces a self-employment tax base of $92,350. The 12.4% Social Security portion stops at the $184,500 wage base for 2026; the 2.9% Medicare portion runs on every dollar.2Social Security Administration. Contribution and Benefit Base
Contractors also owe the 0.9% Additional Medicare Tax once self-employment income crosses the same thresholds that apply to employees.6Office of the Law Revision Counsel. 26 USC 1401 – Rate of Tax You calculate it on Form 8959.
To offset paying both halves of FICA, the tax code lets you deduct half of your self-employment tax when calculating adjusted gross income.7Internal Revenue Service. Schedule SE (Form 1040) – Self-Employment Tax The deduction goes on Schedule 1. It reduces your income tax but does not reduce the self-employment tax itself.
Income Tax and Schedule C
Commission revenue and business expenses go on Schedule C, which produces your net profit.8Internal Revenue Service. Schedule C (Form 1040) – Profit or Loss From Business That net profit feeds into two places: Schedule SE for self-employment tax and Schedule 1 for income tax. Income tax is then calculated using the ordinary progressive brackets, which for 2026 run from 10% on the first $12,400 of taxable income for single filers up to 37% above $640,600.9Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
Deductions matter more for a commission contractor than for almost any other kind of taxpayer. Every legitimate expense reduces both income tax and the 15.3% self-employment tax, so a $1,000 deduction saves you roughly $1,000 times your combined marginal rate. Advertising, travel, office supplies, insurance, professional services, and a portion of home office expenses are all deductible when the use is genuinely business-related. Contractors who don’t track expenses carefully end up paying tax on revenue they never actually kept.
Quarterly Estimated Payments
Since nothing is withheld from a 1099 commission check, the IRS expects contractors to pay in throughout the year using Form 1040-ES.10Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals The trigger is straightforward: if you expect to owe $1,000 or more after subtracting withholding and refundable credits, estimated payments are generally required.11Internal Revenue Service. Estimated Tax
For 2026, the quarterly deadlines are April 15, June 15, September 15, and January 15, 2027. Each payment covers both income tax and self-employment tax for that period.12Taxpayer Advocate Service. Making Estimated Tax Payments When a due date lands on a weekend or holiday, the deadline moves to the next business day. Commission income tends to arrive unevenly, so many contractors base each installment on actual income received in that quarter rather than a full-year projection.
The Underpayment Penalty and How to Avoid It
Miss a quarterly deadline or underpay, and the IRS assesses an underpayment penalty. The rate is 7% per year for the first quarter of 2026, compounded daily, and it resets each quarter.13Internal Revenue Service. Interest Rates Remain the Same for the First Quarter of 2026 The penalty is calculated separately for each quarter you fell short, so one missed installment is enough to trigger it.
The IRS also gives you safe harbors. You avoid the penalty if any of these hold:14Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual To Pay Estimated Income Tax
- You owe less than $1,000 after withholding and refundable credits.
- Your payments for the year totaled at least 90% of what you actually owe for the current year.
- Your payments totaled at least 100% of the tax on last year’s return (assuming that return covered 12 months).
Higher earners get a stricter version of that last rule. If last year’s adjusted gross income exceeded $150,000 ($75,000 for married filing separately), the prior-year safe harbor is 110% of last year’s tax rather than 100%.14Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual To Pay Estimated Income Tax For commission earners with volatile income, the prior-year method is usually the most workable target because the number is known in advance.
When a Commission Becomes Taxable
If you earn a commission in December but don’t cash the check until January, it belongs to December. Under the constructive receipt rule, income is taxable in the year it is credited to your account or made available to you without restriction, whether or not you take possession.15Internal Revenue Service. Publication 538 – Accounting Periods and Methods Holding a check in a drawer does not shift the tax year. Neither does leaving a deposited payment untouched in your account. This applies to cash-basis taxpayers, which covers almost every individual commission earner.
Practical Moves to Avoid a Surprise Bill
Commission income is uneven by nature, and that unevenness is what creates most of the tax problems. A big Q2 followed by a slow Q3 can leave you over-withheld in one period and short in another, or lift your annual bracket above what your salary alone suggests.
W-2 commission earners in the 24%, 32%, or higher brackets should look at their W-4. The 22% flat withholding on supplemental wages often runs below the marginal rate that will actually apply, and the shortfall lands on the April return. Requesting an additional dollar amount per pay period on the W-4 closes that gap without much effort.
For contractors, disciplined deductions do more than anything else. Keep receipts, run business income and expenses through a separate bank account, and log mileage as you go rather than reconstructing it in April. Each dollar of legitimate expense reduces both the income tax and the 15.3% self-employment tax, so recordkeeping produces one of the highest returns on time you can find in personal finance.
One boundary worth flagging: states have their own rules. Many require withholding or estimated payments on commission income, flat supplemental rates vary widely, and federal safe harbors do not protect you from state penalties. Check your state’s requirements separately.