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.
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.
Frequently Asked Questions
What is the Additional Medicare Tax threshold for 2026?
$200,000 for single, head of household, and qualifying widow(er). $250,000 for married filing jointly. $125,000 for married filing separately. These thresholds have NOT changed since 2013 and are NOT indexed for inflation \u2014 they capture more households each year due to wage growth.
Is Additional Medicare Tax the same as NIIT?
No, two separate taxes. Additional Medicare Tax (0.9%) applies to EARNED income (wages, SE) above the threshold. Net Investment Income Tax (3.8%) applies to INVESTMENT income above similar thresholds. High earners with both wage and investment income pay both taxes.
Do I need to pay quarterly estimated tax for Additional Medicare?
Yes if your withholding won't cover it. Self-employed should include the Additional Medicare Tax in their 1040-ES quarterly calculations. Wage earners whose combined household income exceeds the threshold should request additional W-4 withholding from their employer or pay quarterly to avoid underpayment penalty.
Can I deduct Additional Medicare Tax on my return?
No. Unlike regular SE tax (\u00bd deductible above-the-line), Additional Medicare Tax has no deduction. The full 0.9% is paid out of after-tax income. This makes it economically equivalent to a small bracket increase for high earners.
Does Additional Medicare Tax apply to retirement income?
Generally no. Pensions, 401(k) distributions, IRA withdrawals, and Social Security are NOT subject to Additional Medicare Tax. The tax applies only to earned income \u2014 wages, SE income, and railroad compensation. Retirees with large investment income may still owe NIIT (3.8%) on that investment income.
How do I claim already-withheld Additional Medicare Tax?
If your employer withheld too much (e.g., one job had over $200K wages, but your total household stays under the threshold due to filing MFJ), you can reconcile on Form 8959. Excess withholding is added to your regular Medicare withholding amount and refunded if you over-paid total federal tax.