Commission income is taxed as ordinary income, which means every dollar is subject to federal income tax, Social Security, and Medicare whether you earn it as a W-2 employee or a 1099 contractor. What changes is who does the math. If you are an employee, your employer withholds taxes before the commission reaches your account. If you are a contractor, you receive the full amount and owe the entire tax bill yourself, usually in quarterly installments. That single distinction drives how commission income is taxed from paycheck to filing.
How Employers Withhold on W-2 Commissions
The IRS treats commissions paid to employees as “supplemental wages,” the same category as bonuses, severance, and back pay.1Internal Revenue Service. Publication 15 – Employer’s Tax Guide That label gives your employer a choice between two withholding methods.
The first is the flat rate method. When commissions are paid separately from your regular wages, or combined but identified as a distinct amount, the employer can withhold a flat 22% for federal income tax.1Internal Revenue Service. Publication 15 – Employer’s Tax Guide This flat rate applies as long as your total supplemental wages for the year stay at or below $1 million. Most employers prefer this method because the calculation ignores your W-4.
The second is the aggregate method. The employer adds the commission to your regular wages for the pay period and withholds on the combined total using your W-4 and the standard tax tables. Depending on your salary, this can withhold more or less than 22%, and a large commission stacked on a regular paycheck often feels like an unusually heavy withholding hit for that period.
Once your supplemental wages pass $1 million in a calendar year, the rules harden. Every commission dollar above that threshold must be withheld at 37%, the top individual rate, and your W-4 cannot soften it.1Internal Revenue Service. Publication 15 – Employer’s Tax Guide
Social Security and Medicare on Employee Commissions
FICA comes out of every commission payment just as it does from salary. The Social Security portion is 6.2% of wages up to $184,500 in 2026, matched by your employer, with withholding stopping once you hit the cap.2Social Security Administration. Contribution and Benefit Base Medicare runs 1.45% on all wages with no cap, also matched.
Higher earners pick up an extra 0.9% Additional Medicare Tax on wages above $200,000 for single filers, $250,000 for joint filers, and $125,000 for married filing separately.3Internal Revenue Service. Questions and Answers for the Additional Medicare Tax There is no employer match on this piece, so it falls entirely on you. Commission earners run into it often because one strong quarter can push year-to-date wages past the threshold without warning.
Everything, including every commission and every dollar withheld, lands on your Form W-2 after year-end.
How Taxes Work on 1099 Commission Income
Independent contractors receive the gross commission with nothing taken out. The business paying you files Form 1099-NEC at year-end, and the full tax obligation sits with you.4Internal Revenue Service. Form 1099-NEC and Independent Contractors You owe two separate taxes: regular income tax at your marginal rate, and self-employment tax.
Self-Employment Tax
Self-employment tax covers the Social Security and Medicare contributions an employer would normally share with you. As your own employer, you pay both halves: 12.4% for Social Security and 2.9% for Medicare, 15.3% in total.5Internal Revenue Service. Topic No. 554, Self-Employment Tax
The tax does not apply to your full net profit. You first multiply net earnings by 92.35% to get the taxable base, which mirrors how W-2 employees avoid paying FICA on the employer’s share.5Internal Revenue Service. Topic No. 554, Self-Employment Tax On $100,000 of net commission income, self-employment tax applies to $92,350. The 12.4% Social Security portion stops at the same $184,500 wage base, while the 2.9% Medicare portion has no cap.2Social Security Administration. Contribution and Benefit Base
Contractors also owe the 0.9% Additional Medicare Tax once self-employment income passes $200,000 single or $250,000 joint, calculated on Form 8959.6Office of the Law Revision Counsel. 26 USC 1401 – Rate of Tax
To offset paying both halves of FICA, the code lets you deduct half of your self-employment tax when figuring adjusted gross income.7Internal Revenue Service. Schedule SE (Form 1040) – Self-Employment Tax The deduction goes on Schedule 1 and reduces your income tax, though it does not reduce the self-employment tax itself.
Income Tax on Your Net Profit
Commission income and business expenses are reported on Schedule C, which produces your net profit.8Internal Revenue Service. Schedule C (Form 1040) – Profit or Loss From Business That number flows to Schedule SE for self-employment tax and to Schedule 1 for income tax, which is then taxed on the regular progressive brackets.9Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
Deductions carry more weight for contractors than for employees. Each legitimate business expense reduces both your income tax and the 15.3% self-employment tax, so a $1,000 deduction saves roughly $1,000 times your combined marginal rate. Contractors who do not track expenses carefully end up paying tax on revenue they never actually kept.
Quarterly Estimated Payments
Because nothing is withheld from 1099 commissions, the IRS expects you to pay as you go using Form 1040-ES.10Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals You generally have to make these payments if you expect to owe $1,000 or more after withholding and refundable credits.11Internal Revenue Service. Estimated Tax
For tax year 2026, the deadlines are:
- First quarter: April 15, 2026
- Second quarter: June 15, 2026
- Third quarter: September 15, 2026
- Fourth quarter: January 15, 2027
Each payment covers both income tax and self-employment tax for the period.12Taxpayer Advocate Service. Making Estimated Tax Payments If a deadline falls on a weekend or holiday, it shifts to the next business day. Commission income can swing hard from quarter to quarter, so many contractors base each payment on actual income received rather than a full-year forecast.
Avoiding the Underpayment Penalty
Missed or short payments trigger an underpayment penalty, currently 7% per year, compounded daily, with the rate adjusting quarterly.13Internal Revenue Service. Interest Rates Remain the Same for the First Quarter of 2026 The penalty is calculated separately for each quarter, so one short payment is enough.
You avoid the penalty if any one of these safe harbors applies: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 totaled at least 90% of the current year’s tax.
- Your payments totaled at least 100% of the prior year’s tax, if that return covered a full 12 months.
Higher earners face a tighter version. If your prior-year adjusted gross income was over $150,000 ($75,000 for married filing separately), the prior-year safe harbor rises to 110% of last year’s tax.14Office of the Law Revision Counsel. 26 USC 6654 – Failure by Individual To Pay Estimated Income Tax A strong year sets a high bar for the next, which catches commission earners regularly. Even so, the prior-year method is the most predictable path when income is volatile, because the number is fixed in advance.
Which Tax Year a Commission Belongs To
If you earn a commission in December but hold the check until January, the IRS still counts it as December income 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 Leaving a check in a desk drawer does not move it into the next tax year, and the same logic applies to a payment deposited into your account that you choose not to withdraw. This governs cash-basis taxpayers, which covers most individual commission earners.
Practical Adjustments for Uneven Commission Income
Lumpy commission income creates tax problems that a steady salary rarely does. A big Q2 followed by a quiet Q3 can leave you over-withheld in one period and short in another, and a strong year can push you into a higher marginal bracket than your base salary alone would predict.
W-2 employees who earn significant commissions can submit a new W-4 asking for additional withholding on regular paychecks. The 22% flat rate on supplemental wages often falls short of the actual marginal rate for someone in the 24%, 32%, or higher bracket. An extra flat dollar amount per pay period closes the gap before April.
Contractors have more direct leverage because every deduction cuts both income tax and self-employment tax. Schedule C allows deductions for advertising, vehicle expenses, office supplies, insurance, professional services, travel, and home office costs, among others.8Internal Revenue Service. Schedule C (Form 1040) – Profit or Loss From Business Keep receipts and track mileage as it happens rather than reconstructing it at year-end.
States run their own rules. Flat withholding rates on supplemental wages vary widely, and some states require their own estimated payments. The federal safe harbors do not shield you from state shortfalls, so check your state’s requirements separately.