Additional Medicare Tax Calculator (0.9%)
Estimate the 0.9% Additional Medicare Tax on wages, self-employment, and RRTA income. Computes Form 8959 totals and reconciles withholding for 2026.
Additional Medicare Tax Calculator (0.9%)
Filing Status
Medicare Wages
W-2 box 5, all jobs combined
Self-Employment Earnings
Schedule SE Part I line 6 (net of the 0.9235 factor)
Uncheck if you entered raw Schedule C profit. The calculator will apply the 0.9235 net-earnings factor.
RRTA Compensation
Railroad retirement (Tier I + Tier II Medicare wages). Leave at 0 if not applicable.
Additional Medicare Tax Already Withheld
From W-2 box 14 or the 0.9% your employer took on wages above $200,000.
Form 8959 line 18 flows to Schedule 2 (Form 1040) line 11. Any excess employer withholding flows to Form 1040 line 25c.
Get Your Full Tax Estimate
This calculator covers the 0.9% surtax in isolation. Tax47 ties it back to your full return: brackets, FICA, credits, and state tax.
How the 0.9% Additional Medicare Tax works
The Additional Medicare Tax took effect in 2013 as part of the Affordable Care Act. It's a flat 0.9% surtax that sits on top of the regular 1.45% Medicare tax, but only the employee pays it. Employers don't match the 0.9% the way they match the base 1.45%.
The tax base is broad: Medicare wages reported in W-2 box 5, self-employment net earnings from Schedule SE, and railroad retirement (RRTA) compensation. Each base has its own line on Form 8959, but they all use the same 0.9% rate and the same filing-status threshold.
To see how the surtax interacts with the rest of payroll, check our FICA payroll tax calculator for the 1.45% Medicare and 6.2% Social Security base.
2026 thresholds by filing status
The dollar thresholds are statutory. They haven't been indexed for inflation since the tax took effect, and the One Big Beautiful Bill Act (P.L. 119-21) didn't change them for 2026.
| Filing status | Threshold |
|---|---|
| Single | $200,000 |
| Head of Household | $200,000 |
| Qualifying Surviving Spouse | $200,000 |
| Married Filing Jointly | $250,000 |
| Married Filing Separately | $125,000 |
Note the gap: a married couple filing jointly gets a $250,000 threshold, not the $400,000 you might expect from doubling the single amount. That mismatch is one reason dual-income households often owe at filing.
Form 8959 walkthrough
Form 8959 has five parts. Part I handles wages: subtract the filing-status threshold from total Medicare wages and multiply the excess by 0.9% to get line 7. Part II handles self-employment, where the threshold is first reduced by Medicare wages (so wages and SE income share one threshold), and SE income above what's left is taxed at 0.9% on line 13.
Part III handles RRTA compensation against its own threshold (line 17). Part IV totals lines 7, 13, and 17 into line 18, which flows to Schedule 2 (Form 1040) line 11. Part V reconciles withholding: line 21 is the 0.9% your employer took on wages above $200,000, and line 24 carries any excess to Form 1040 line 25c as a credit.
If you're estimating quarterly payments to cover this surtax, our estimated quarterly tax calculator can fold the result into your total. For the deductible half of SE tax, see the self-employment tax calculator.
The withholding mismatch problem
Employers must start withholding the 0.9% on any individual employee whose wages cross $200,000 in a calendar year, regardless of filing status. They have no visibility into a spouse's wages, so the system relies on Form 8959 to reconcile at filing time.
Two common mismatches show up. The first hits dual-earner couples where neither spouse hits $200,000 individually but combined wages exceed the $250,000 MFJ threshold. Neither employer withheld, so the couple owes the surtax at filing. The second hits single filers with one job slightly above $200,000, who may see exact withholding, while a head-of-household filer at the same $200,000 threshold with wages straddling the line can end up under-withheld once SE income is added.
If your calculator result shows a balance owed, you can adjust W-4 line 4c additional withholding or pay quarterly estimates. If it shows excess withholding, that amount becomes a refundable credit on Form 1040 line 25c. You can see the full Medicare picture in the Tax47 app, which folds the surtax into your overall refund estimate alongside brackets, credits, and state tax. For investment-income surtaxes that often appear on the same return, our MAGI calculator covers the Net Investment Income Tax threshold companion.
Estimates only. Not tax or legal advice.
Frequently Asked Questions
Common questions about additional medicare tax calculator (0.9%)
What is the Additional Medicare Tax?
It's a 0.9% surtax enacted in 2013 under the Affordable Care Act. It applies to Medicare wages, self-employment income, and RRTA compensation above filing-status thresholds. Only the employee owes it. Employers do not match the 0.9% the way they match the regular 1.45% Medicare tax.
Who has to pay the Additional Medicare Tax in 2026?
Anyone whose combined Medicare wages, self-employment earnings, and RRTA compensation exceed $200,000 (single, head of household, or qualifying surviving spouse), $250,000 (married filing jointly), or $125,000 (married filing separately).
Did the One Big Beautiful Bill Act change the Additional Medicare Tax thresholds?
No. The Act (P.L. 119-21) left the 0.9% rate and the dollar thresholds alone. The thresholds are statutory and haven't been indexed for inflation since the tax took effect in 2013.
How is the Additional Medicare Tax calculated for self-employed people?
Start with Schedule SE Part I line 6, which is net earnings from self-employment (already multiplied by 0.9235). Reduce your filing-status threshold by any Medicare wages you also received. Multiply the self-employment income above that reduced threshold by 0.9%.
Why does my employer withhold the 0.9% on wages over $200,000 even if I file jointly?
Federal rules require every employer to start withholding the 0.9% once an individual employee's wages cross $200,000 in a calendar year, no matter the filing status. Employers don't see spousal income, so the reconciliation happens on Form 8959 at filing time.
What if my spouse and I each earn under $200,000 but together exceed $250,000?
Neither employer will withhold the 0.9% because each spouse stays under the $200,000 employer trigger, but you still owe it on the amount above $250,000 MFJ. Pay it with estimated taxes or expect a balance due when you file Form 8959.
How is the Additional Medicare Tax reported?
Compute it on Form 8959. The total from line 18 flows to Schedule 2 (Form 1040), line 11. Any over-withholding from line 24 of Form 8959 flows to Form 1040 line 25c as a refundable credit.
Is the Additional Medicare Tax deductible?
No. Unlike the deductible half of self-employment tax, the employee-side Additional Medicare Tax can't be deducted against income. It's a flat surtax on top of regular Medicare tax.