US Additional Medicare Tax Calculator: 0.9% on High Earners
Work out the US Additional Medicare Tax — the extra 0.9% high earners owe on wages and self-employment income above a threshold — on the portion of your earnings that exceeds it.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Additional Medicare Tax | Excess net of tax |
|---|---|---|
| 0.9% of $50,000 over ($450) | 450 | 49,550 |
| 0.9% of $100,000 over | 900 | 99,100 |
| 0.9% of $25,000 over | 225 | 24,775 |
| 0.9% of $300,000 over | 2,700 | 297,300 |
How This Calculator Works
Enter the 0.9% rate and your earnings above your filing-status threshold (not your full income — only the excess). The calculator returns the Additional Medicare Tax. The thresholds are $200,000 for single filers and $250,000 for married filing jointly (these are not indexed for inflation), so only income above those amounts is subject to the extra 0.9%.
The Formula
Percentage of an Amount
Amount is the base value, Percentage is the rate applied to it
Worked Example
If your earnings exceed the threshold by $50,000, the Additional Medicare Tax is $450 (0.9% of $50,000). This tax is on top of the regular 1.45% Medicare portion of FICA — so wages above the threshold are effectively taxed at 2.35% for Medicare (1.45% + 0.9%). It applies to wages, compensation, and self-employment income above the threshold, but unlike the employer-matched regular Medicare tax, there is no employer match on the additional 0.9% — the employee bears it entirely.
Key Insight
The Additional Medicare Tax is a 0.9% surtax introduced under the Affordable Care Act, and a few specifics matter for high earners. It applies only to earned income (wages, RRTA compensation, and self-employment income) above the threshold for your filing status: $200,000 single/head of household, $250,000 married filing jointly, and $125,000 married filing separately — and notably these thresholds are not indexed for inflation, so over time more taxpayers cross them. Employers must begin withholding the extra 0.9% once an employee's wages from that employer exceed $200,000, regardless of filing status — which means withholding can be too much or too little versus your actual liability (e.g. a married couple each earning $150,000 has $300,000 combined, owing the tax on $50,000, but neither employer withholds it; conversely a single high earner may have it over-withheld), so it's reconciled on your tax return. Don't confuse it with the separate 3.8% Net Investment Income Tax (NIIT), which applies to investment income above similar thresholds — they're two different ACA surtaxes, and a high earner can owe both on different income types. This calculator computes the 0.9% on the excess earnings you enter; to find your actual liability, determine how much of your earned income exceeds your filing-status threshold and apply 0.9% to that amount. For self-employed taxpayers, the 0.9% is in addition to the regular Medicare portion of self-employment tax on income above the threshold. Confirm current thresholds and rules with the IRS or a tax professional.
Why dual-income MFJ couples often face year-end shock
Employer withholds Additional Medicare Tax based on INDIVIDUAL wages above $200K. Each employer sees only its own wages — doesn't know spouse's earnings.
Couple A: spouse 1 earns $180K, spouse 2 earns $180K = combined $360K. Neither employer withholds Additional Medicare Tax (each below $200K individual threshold). At tax filing, MFJ threshold is $250K — combined $360K means $110K subject to Additional Medicare Tax = $990 owed at year-end. No withholding occurred during year.
Couple B: single earner with $300K. Employer withholds Additional Medicare Tax on $100K above $200K = $900. At filing, MFJ threshold $250K, so $50K subject to Additional Medicare Tax = $450 owed. Employer withheld $900 — refund $450.
Result: dual-earner couples face year-end Additional Medicare Tax liability while single-earner couples may get refund. Plan for this — make estimated tax payments or increase withholding via Form W-4 if both spouses earn substantial wages.
Self-employed and Additional Medicare Tax
Self-employed pay BOTH employer and employee shares of FICA (15.3% combined regular SE tax). Plus Additional Medicare Tax 0.9% on net earnings above threshold.
Combined Medicare rate for self-employed earning above threshold: 2.9% regular Medicare (both halves) + 0.9% Additional Medicare = 3.8% total. Plus 12.4% Social Security (subject to wage base $168,600). Plus federal income tax 24-37%. Plus state.
Total marginal rate for high-earning self-employed (35%+ federal bracket): SE tax + federal + state can exceed 50%. Substantial planning to manage. (1) S-corp election — pay reasonable salary subject to FICA, take distributions free of SE tax (Additional Medicare Tax still applies to wages). (2) Retirement contributions — SEP IRA, Solo 401(k) reduce taxable income.
(3) QBI deduction — 20% deduction on qualified business income reduces effective rate. (4) Spouse employment — paying spouse salary may shift income to lower bracket family member.
For self-employed with $300K+ net earnings, comprehensive tax planning typically saves $10K-$50K+ annually compared to default sole proprietor treatment.
Additional Medicare Tax scenarios (2024)
Reference Additional Medicare Tax calculation by income level.
| Filing status | Wages/SE income | Above threshold | Additional Medicare Tax (0.9%) |
|---|---|---|---|
| Single | $200K | $0 | $0 |
| Single | $250K | $50K | $450 |
| Single | $400K | $200K | $1,800 |
| MFJ | $200K combined | $0 | $0 |
| MFJ | $250K combined | $0 | $0 |
| MFJ | $350K combined | $100K | $900 |
| MFJ | $500K combined | $250K | $2,250 |
| Self-employed (SE) | $300K net SE | $100K | $900 + regular SE tax |
Threshold varies by filing status: $200K single, $250K MFJ, $125K MFS. Employer withholding based on individual wages above $200K regardless of filing status — dual-income MFJ couples often owe at year-end. Self-employed pay Additional Medicare Tax via Schedule SE (Form 1040).
Frequently Asked Questions
How is the Additional Medicare Tax calculated?
Multiply your earnings above the filing-status threshold by 0.9%. If you're $50,000 over the threshold, the tax is $450. It applies only to the excess above the threshold, not your entire income.
What are the thresholds?
$200,000 for single and head-of-household filers, $250,000 for married filing jointly, and $125,000 for married filing separately. Only earned income (wages and self-employment income) above your threshold is subject to the extra 0.9%. The thresholds are not indexed for inflation.
Is this on top of regular Medicare tax?
Yes. It's in addition to the regular 1.45% Medicare portion of FICA, so wages above the threshold are effectively taxed at 2.35% for Medicare (1.45% + 0.9%). Unlike the regular Medicare tax, there's no employer match on the additional 0.9% — the employee bears it entirely.
Why might my withholding be wrong?
Employers withhold the 0.9% once your wages from that employer exceed $200,000, regardless of filing status. So a married couple each earning $150,000 owes the tax but has none withheld, while a single high earner might have it over-withheld. It's reconciled on your tax return, where the actual liability is calculated.
Is this the same as the 3.8% Net Investment Income Tax?
No — they're two different ACA surtaxes. The Additional Medicare Tax (0.9%) applies to earned income above the threshold; the Net Investment Income Tax (3.8%) applies to investment income above similar thresholds. A high earner can owe both, on different types of income. Don't confuse them.
When is this calculator unreliable?
For dual-income MFJ couples where employer withholding may not capture full liability (each employer only sees its own wages; combined wages above $250K MFJ threshold create liability not withheld). Make estimated payments or W-4 adjustments to avoid year-end shock. Also unreliable for self-employed who pay Additional Medicare Tax via Schedule SE alongside regular SE tax.
References & Authoritative Sources
- Internal Revenue Service (IRS) — Additional Medicare Tax · consulted June 1, 2026 · Federal regulator on Additional Medicare Tax
- Joint Committee on Taxation (JCT) — ACA Medicare Tax Provisions · consulted June 1, 2026 · Congressional analysis of Additional Medicare Tax
- Tax Foundation — Medicare Tax Research · consulted June 1, 2026 · Authoritative Medicare tax research
Related Calculators
Methodology & Review
Additional Medicare Tax equals (wages + SE income + RRTA compensation above threshold) × 0.9%. The calculator returns additional Medicare tax. Thresholds 2024: $200K single; $250K MFJ; $125K MFS. Added by ACA (2013). Applies to W-2 wages, self-employment income, and railroad compensation. Distinct from regular Medicare tax (1.45% employee + 1.45% employer = 2.9% combined). Effectively brings top combined Medicare rate to 3.8% on high earnings. RELIABILITY: Reliable for direct calculation. Less reliable for accurate withholding because (a) employer only withholds Additional Medicare Tax on individual employee wages above $200K (regardless of filing status); married couples may owe additional at year-end if combined wages exceed $250K MFJ threshold; (b) self-employed pay both halves with Additional Medicare Tax.
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