The additional Medicare tax is an extra 0.9% tax on wages above $200,000 for single filers ($250,000 if married filing jointly, $125,000 if married filing separately). It stacks on top of the regular 1.45% Medicare tax, so wages past the line are taxed at 2.35% for Medicare alone. Employers must start withholding it in the pay period when your year-to-date wages from that employer cross $200,000 — and unlike regular Medicare, there is no employer match.
A concrete example: a single filer earning $260,000 owes the extra 0.9% on $60,000 of wages — $540 for the year. Whether that $540 was already withheld from your paychecks, or shows up as a surprise balance due in April, depends on how your pay is split across jobs and what your filing status is. Here is how the withholding trigger, the actual liability, and the Form 8959 reconciliation fit together.
Every paycheck already carries a 1.45% Medicare tax on every dollar of wages, with no cap — that has been true for decades and it applies from your first dollar of pay. The additional Medicare tax is a second, newer layer that only touches higher earners: once your wages pass the threshold for your filing status, each additional dollar of wages is taxed at 1.45% plus 0.9%, for a combined Medicare rate of 2.35%.
Three features make this tax different from everything else on your pay stub. First, it is employee-only: your employer matches your regular 1.45% Medicare tax dollar for dollar, but pays nothing toward the extra 0.9%. Second, it has nothing to do with Social Security — the 6.2% Social Security tax still stops at the $184,500 wage base for 2026, and that cap neither raises nor lowers your additional Medicare tax. Third, there is no standard deduction sheltering the first dollars the way there is with income tax (single filers get a $16,100 standard deduction against federal income tax in 2026, taxed at 10% to 37%). Medicare taxes, regular and additional, apply to gross wages as defined on your W-2 — your Medicare wages are the number in Box 5.
One common mix-up: this is not the 3.8% tax on investment income you may have heard about. The 0.9% applies only to wages and self-employment income. The 3.8% net investment income tax applies to interest, dividends, capital gains, and similar income, uses modified adjusted gross income instead of wages, and is computed on a different form. High earners can owe both, but they never overlap on the same dollar.
Take a single filer earning $260,000 a year, paid biweekly — $10,000 per paycheck, one job, no other income. Their actual liability is easy: wages over the $200,000 single-filer threshold are $60,000, times 0.9%, equals $540 of additional Medicare tax for the year. The regular Medicare tax on the full $260,000 is a separate $3,770 (1.45%), and Social Security tax stopped partway through the year at $11,439 (6.2% of the $184,500 wage base).
Now the withholding side. The employer does not know this employee's filing status or total income — it only sees wages it pays. So payroll starts withholding the extra 0.9% in the first pay period after year-to-date wages pass $200,000, which for this earner happens in late October (after the 20th biweekly check). From then on, each $10,000 paycheck carries an extra $90 of Medicare withholding on top of the usual $145. The withholding applies to the wages above $200,000 paid by that employer: $60,000 over the rest of the year, times 0.9%, equals $540.
For this one-job single filer, withholding and liability match exactly — $540 withheld, $540 owed, nothing to settle in April. That clean match is the exception, not the rule, as the next section shows. If you want to see where your own pay crosses the line, the FICA tax calculator breaks out the Medicare portion of a paycheck at any salary.
Here is the detail that generates surprise tax bills. Withholding is triggered by one number only: $200,000 of wages from a single employer, no matter your filing status, your spouse's income, or your other jobs. Liability is computed on your tax return using your filing status: $200,000 single, $250,000 married filing jointly, $125,000 married filing separately. When those two systems look at different numbers, money is over- or under-withheld by design.
Case one: a married couple each earning $150,000. Neither employer sees wages over $200,000, so neither withholds a cent of additional Medicare tax. But their combined wages are $300,000 against a $250,000 joint threshold, so they owe 0.9% on $50,000 — $450 due with their return, none of it prepaid. Case two: a single filer with two jobs paying $150,000 each. Same story from the other side of the threshold: no withholding anywhere, but a $300,000 total against a $200,000 threshold means 0.9% on $100,000 — $900 owed.
The mismatch runs the other way too. A married employee earning $230,000 whose spouse does not work will have the extra 0.9% withheld on $30,000 of wages — $270 taken during the year — even though the couple's $250,000 joint threshold means they owe nothing at all. That $270 is not lost; it comes back through the reconciliation on Form 8959 as part of their refund. But it is an interest-free loan to the IRS in the meantime, and it confuses people every year because the pay stub line looks like a mistake.
A useful habit: the first time you see a second Medicare line (often labeled "Addl Med" or "Medicare Surtax") on a fall pay stub, do a five-minute projection. Estimate your full-year wages from all jobs, add your spouse's if you file jointly, and compare against your filing-status threshold. If withholding will fall short, the fix is simple — request extra federal withholding on your W-4 or make an estimated payment. Our tax withholding calculator can help size the adjustment.
If you freelance or run a business, there is no employer watching the $200,000 line for you, but the tax still applies. The additional Medicare tax covers the combination of your W-2 wages and your net self-employment income: once the combined total passes your filing-status threshold, the excess is taxed at the extra 0.9%. A consultant with $120,000 of W-2 wages and $110,000 of self-employment profit is over the single-filer threshold by $30,000 and owes $270 of additional Medicare tax on top of regular self-employment tax.
Two practical differences from the employee version. You settle it through quarterly estimated payments rather than withholding, so a high-earning year needs to be planned for — discovering a four-figure additional Medicare bill in April, on top of regular self-employment tax, is a common and unpleasant surprise. And the 0.9% is not part of the "employer half" of self-employment tax you can deduct on your return; that deduction covers half of the regular 15.3% self-employment tax only. The self-employment tax calculator shows the regular tax at your income level; add 0.9% on earnings above your threshold for the full picture.
The reconciliation happens on Form 8959, Additional Medicare Tax, which attaches to your Form 1040. The form recomputes the tax from scratch — your Medicare wages from each W-2 (Box 5), any self-employment income, and your filing-status threshold — and then compares the result with what was actually withheld. Amounts your employers withheld show up in Box 6 of your W-2, which includes both the regular 1.45% and any additional 0.9%; the form separates the two so the extra withholding can be credited against the extra tax.
If withholding exceeded the tax (the married $230,000 earner above), the excess flows into your total payments and increases your refund or reduces what you owe. If the tax exceeded withholding (the two-job and dual-earner cases), the shortfall is added to your tax bill. Either way, nothing is final until this form runs — which is why a pay stub showing "Addl Med" withholding does not by itself prove you owe the tax, and a pay stub without it does not prove you don't.
One penalty note: a large shortfall discovered at filing time is treated like any other underpayment. If you expect the two-job or dual-earner gap, covering it during the year — extra W-4 withholding on the higher-paying job, or an estimated payment — keeps you inside the usual safe harbors and avoids an underpayment penalty on top of the tax itself.
Anyone whose wages (plus self-employment income, if any) exceed $200,000 as a single filer, $250,000 if married filing jointly, or $125,000 if married filing separately. The extra 0.9% applies only to the amount above the threshold, on top of the regular 1.45% Medicare tax that applies from the first dollar.
No. The regular 1.45% Medicare tax is matched dollar for dollar by your employer, but the additional 0.9% is paid by the employee only. Employers are still required to withhold it once your wages from that employer pass $200,000 in a calendar year.
Employers must withhold based solely on wages they pay you: the withholding trigger is $200,000 from one employer, regardless of your filing status or household income. A married employee over $200,000 at one job gets the withholding even if the couple's $250,000 joint threshold means no tax is owed. Form 8959 credits it back when you file.
No. The additional Medicare tax is 0.9% and applies only to wages and self-employment income above the thresholds. The 3.8% net investment income tax applies to interest, dividends, capital gains, and similar income, measured against modified adjusted gross income. They are computed on different forms and never tax the same dollar twice.
That happens with two jobs or two working spouses, where no single employer crosses $200,000. The tax is computed on Form 8959 and added to your bill. To avoid a balance due (and a possible underpayment penalty), add extra withholding on your W-4 at one job or make estimated tax payments during the year.