Additional Medicare Tax Calculator 2026 β Form 8959 (0.9%)
Calculate the 0.9% Additional Medicare Tax on wages and self-employment income above $200K/$250K thresholds. Check employer withholding shortage or overage.
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Only applies when MFJ is selected above $0
Additional Medicare Tax Owed
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Threshold for Your Status
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Income Above Threshold
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Withholding Shortage / (Overage)
Additional Medicare Tax Breakdown
How to Use This Additional Medicare Tax Calculator
Select your filing status, enter your W-2 wages and any self-employment net earnings. For Married Filing Jointly, also enter your spouse's W-2 wages. The calculator determines your threshold, excess income, and the 0.9% Additional Medicare Tax owed on Form 8959, plus compares against what your employer already withheld.
Thresholds (2026)
Single / Head of Household: $200,000
Married Filing Jointly (MFJ): $250,000
Married Filing Separately (MFS): $125,000
Employer withholds at: $200,000 (regardless of filing status)
Additional Medicare Tax = (W-2 + SE Income β Threshold) Γ 0.9%
Married Filing Jointly (MFJ): $250,000
Married Filing Separately (MFS): $125,000
Employer withholds at: $200,000 (regardless of filing status)
Additional Medicare Tax = (W-2 + SE Income β Threshold) Γ 0.9%
Example
MFJ couple: Spouse A earns $180,000 W-2, Spouse B earns $120,000 W-2:
Combined income: $300,000
MFJ threshold: $250,000
Excess: $50,000
Additional Medicare Tax: $50,000 Γ 0.9% = $450
Employer withholding: $0 (neither exceeds $200K individually)
Shortage: $450 β reconcile on Form 8959
Combined income: $300,000
MFJ threshold: $250,000
Excess: $50,000
Additional Medicare Tax: $50,000 Γ 0.9% = $450
Employer withholding: $0 (neither exceeds $200K individually)
Shortage: $450 β reconcile on Form 8959
Extended
NIIT Interaction + High Earner Total Tax Analysis
Net Investment Income Tax (3.8%) combined impact for high earners
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Dividends + capital gains + rental income + passive income $
NIIT + Additional Medicare Tax β High Earner Combined Analysis
Effective Tax Rate on Investment Income (Top Bracket)
Frequently Asked Questions
What is the Additional Medicare Tax and who pays it?
The Additional Medicare Tax (AMT) is a 0.9% surtax on wages, self-employment income, and Railroad Retirement Tax Act (RRTA) compensation above threshold amounts. For 2026: Single/MFS/Head of Household filers owe it on income above $200,000; Married Filing Jointly on income above $250,000; Married Filing Separately on income above $125,000. It applies to all US taxpayers, not just high earners β once threshold is crossed, all dollars above it are subject to the 0.9%.
How does employer withholding work for the Additional Medicare Tax?
Employers must withhold Additional Medicare Tax on wages they pay you that exceed $200,000 in a calendar year β regardless of your actual filing status. So if you are Married Filing Jointly with a $250,000 threshold, your employer still starts withholding at $200,000. This can create an under-withholding situation for MFJ filers. Conversely, MFS filers with $125K threshold may have over-withheld. You reconcile the difference on Form 8959 filed with your 1040.
How is the Additional Medicare Tax different from the regular Medicare tax?
Regular Medicare tax is 1.45% on all wages for both employee and employer (2.9% total for self-employed). The Additional Medicare Tax is an extra 0.9% only on the employee/self-employed portion β the employer does NOT pay the additional 0.9%. So the total Medicare rate for high earners is 1.45% + 0.9% = 2.35% on wages above the threshold (or 2.9% + 0.9% = 3.8% on SE income above threshold).
What is Net Investment Income Tax and how does it relate to Additional Medicare Tax?
The Net Investment Income Tax (NIIT) is a separate 3.8% tax on the lesser of: (a) net investment income (dividends, capital gains, rental income, passive income), or (b) the excess of Modified AGI over the same thresholds ($200K single, $250K MFJ). High earners can face both the 0.9% Additional Medicare Tax on earned income AND 3.8% NIIT on investment income simultaneously, creating an effective 43.4% federal rate on investment income (37% bracket + 3.8% NIIT + potential surtaxes).
Does the Additional Medicare Tax apply to self-employment income?
Yes. For self-employed individuals, the 0.9% Additional Medicare Tax applies to net self-employment (SE) earnings above the applicable threshold. Unlike regular SE tax where you can deduct half the SE tax before applying the rate, there is no equivalent deduction for the 0.9% Additional Medicare Tax. The combined W-2 wages plus SE income determine whether the threshold is crossed for self-employed individuals who also have wage income.