United States · Self-employed · Form 8959
Additional Medicare Tax calculator for the self-employed.
The 0.9% Additional Medicare Tax uses a threshold that your W-2 Medicare wages reduce. Enter both sides of your income to see the self-employment part. Runs in your browser.
A single filer with $150,000 of Medicare wages and $100,000 of net self-employment profit owes about $381.15 of Additional Medicare Tax, all on the self-employment side, because the wages cut the $200,000 threshold to $50,000. With no wages the same profit owes $0.00.
How this is calculated
- Self-employment income is net profit times 92.35% (Schedule SE, line 6).
- Threshold is $250,000 married filing jointly, $125,000 married filing separately and $200,000 otherwise. These amounts are set by statute and are not indexed for inflation.
- Wages first. Medicare wages above the threshold are taxed at 0.9% (Form 8959, Part I).
- Reduced threshold. For self-employment income the threshold is reduced, but not below zero, by your Medicare wages (Part II). Self-employment losses are ignored.
- Add the two parts, then subtract Additional Medicare Tax your employers withheld to see what remains to cover through estimated payments or at filing.
Worked examples
| Scenario | Result |
|---|---|
| Single, $100,000 profit, no wages | SE earnings $92,350 is under $200,000; tax $0.00 |
| Single, $100,000 profit, $150,000 wages | Threshold left $50,000; tax on $92,350 less that = $381.15 |
| Joint, $200,000 profit, $100,000 wages | SE earnings $184,700; threshold left $150,000; tax $312.30 |
The first line shows why a $100,000 profit alone does not trigger the tax, while the same profit stacked on a large salary does.
What this does not cover
- Regular self-employment tax, income tax or the 3.8% Net Investment Income Tax (a separate tax).
- Railroad retirement (RRTA) compensation, where the threshold is not reduced.
- Tax from a spouse whose income is separate when filing separately, beyond the figures you enter.
- Estimated-payment timing. Use the quarterly estimated tax calculator and add this amount to your expected tax.
- Wages over $200,000 at any one employer: employers withhold on that basis regardless of filing status, so your final tax can differ from withholding.
Method and assumptions
The calculation mirrors Form 8959 Parts I and II using only the numbers you enter. Net profit is converted to self-employment earnings with the 92.35% factor. Rounding follows cents rather than whole dollars, so the result can differ slightly from a filed return.
Results vary with your actual income, deductions, credits and filing situation. This page uses the figures you enter and published IRS rules; it does not predict what you will earn or owe. This is general information, not tax, legal or accounting advice; confirm your own situation against the linked IRS instructions or with a qualified preparer. Nothing here collects or stores personal data.
Sources
- IRS Instructions for Form 8959 (Additional Medicare Tax), retrieved October 2026
- IRS: Self-employment tax (Social Security and Medicare taxes), retrieved October 2026
- IRS Topic no. 751, Social Security and Medicare withholding rates ($184,500 wage base for 2026), retrieved October 2026
Cite this page: TNAADO Tools, "Additional Medicare Tax calculator for the self-employed," tools.tnaado.ca/us/additional-medicare-tax-self-employed-calculator/, figures retrieved October 2026.
Frequently asked questions
Does the Additional Medicare Tax apply to self-employment income?
Yes. Form 8959 taxes self-employment income at 0.9% to the extent it exceeds the threshold for your filing status, reduced by any Medicare wages you also have.
What are the thresholds?
$250,000 for married filing jointly, $125,000 for married filing separately and $200,000 for single, head of household and qualifying surviving spouse. The IRS notes that these amounts are not indexed for inflation.
Do my W-2 wages change the self-employment threshold?
Yes. The self-employment threshold is reduced, but not below zero, by your Medicare wages. A $150,000 salary leaves only $50,000 of the $200,000 threshold for self-employment income.
Is half of this tax deductible like regular self-employment tax?
No. The deduction covers the Social Security and Medicare portions of self-employment tax, not the 0.9% Additional Medicare Tax.
Is this tax advice or a prediction?
Neither. It applies published IRS rules to the figures you enter. Results vary with your actual wages, profit, filing status and withholding.
Not tax advice
This is an educational estimate built from the numbers you enter and published IRS rules. It is not tax advice and does not predict what you will earn or owe. Self-employed in Canada instead? Use the Canadian self-employment tax calculator.