Additional Medicare Tax Calculator (0.9%)

Calculate the 0.9% Additional Medicare Tax that applies to high-income wages and self-employment income, on top of regular 1.45% Medicare.

Railroad workers — usually $0
If MFJ — combined threshold
Employer withholds 0.9% on wages > $200K only
Total Additional Medicare Tax
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0.9% on income above your threshold
Threshold
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Combined Income
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Amount Over Threshold
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0.9% Tax Owed
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Less Already Withheld
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SE Adjustment (0.9% / 2)
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What Is the Additional Medicare Tax?

The Additional Medicare Tax is a 0.9% federal tax on wages, self-employment income, and railroad retirement compensation above specific income thresholds. Created by the Affordable Care Act (Section 3101(b)(2)), it took effect January 1, 2013 and applies indefinitely. Unlike regular Medicare tax (1.45% employer + 1.45% employee), the Additional Medicare Tax is paid ONLY by the employee — no employer match.

2026 thresholds: $200,000 single, $250,000 MFJ, $200,000 HoH, $125,000 MFS. These thresholds are NOT indexed to inflation — they've stayed fixed since 2013. Every year more Americans owe this tax purely due to wage growth. Source: IRS Section 3101(b)(2), Form 8959. Last updated: May 2026.

Why Withholding Often Doesn't Cover the Liability

Employers are required to begin withholding the 0.9% on wages above $200,000 per employee, regardless of filing status. The mismatch: Married Filing Jointly couples have a $250K threshold but their EACH employer withholds based on $200K. So if Spouse A earns $150K and Spouse B earns $180K, neither hits $200K alone — no withholding — but combined $330K is $80K over the $250K threshold, owing $720 Additional Medicare Tax.

This creates a surprise tax bill for many dual-income couples. Use Form 8959 with your 1040 to calculate the actual liability and the gap from what was withheld.

Self-Employment Adjustment

Self-employment net earnings are first multiplied by 0.9235 (the same adjustment factor used for regular SE tax). The result is added to wages for the threshold test. Example: $100K wages + $50K net SE = $100K + ($50K × 0.9235) = $146,175 combined for the Additional Medicare Tax calculation. SE-only filers can underpay because there's no W-2 withholding to catch them — pay quarterly estimated tax to avoid penalty.

Stacking with Other High-Earner Taxes

High earners face multiple stacked surcharges: (1) Regular Medicare (1.45%) on all wages. (2) Additional Medicare (0.9%) on wages over threshold. (3) Net Investment Income Tax (3.8%) on investment income over threshold. (4) Federal income tax (32-37%) at top brackets. Effective marginal rate on the next dollar earned by a high earner can reach 45%+ federal + state. Plan around recognition timing of bonuses, gains, and SE income.