What the Medicare surtax is and who pays it

The Medicare surtax is an extra 0.9% tax on wages and self-employment income, plus a 3.8% tax on certain investment income. It was added to the tax code in 2013 as part of the Affordable Care Act. Unlike the regular Medicare payroll tax (which is 2.9% total), the surtax only applies to people whose income exceeds a certain threshold.

The income thresholds depend on your filing status. If you file as single, you pay the surtax on income above $200,000. If you file as married filing jointly, the threshold is $250,000. If you file as married filing separately, it is $125,000. These thresholds do not change year to year, even as inflation rises.

The surtax comes out of your paycheck automatically if you are an employee earning over the threshold. If you are self-employed, you pay it when you file your tax return. If you have investment income — from stocks, bonds, rental property, or capital gains — you may owe the 3.8% investment surtax as well.

Key Takeaways

  • The Medicare surtax is 0.9% on wages above $200,000 (single) or $250,000 (married filing jointly), plus 3.8% on investment income above those same thresholds.
  • Your employer withholds the wage surtax automatically if your income crosses the threshold, but you are responsible for reporting and paying the investment surtax yourself.
  • The income thresholds are fixed and do not adjust for inflation, so more people may owe the surtax as their income grows over time.
  • The surtax money goes into the Medicare Hospital Insurance Trust Fund, not into a separate account tied to your benefits.

How the wage surtax works

If you are an employee and your employer knows your income will exceed the threshold in a given year, they should withhold the 0.9% surtax from your paycheck. The withholding begins once you cross the threshold and continues for the rest of the year.

The tricky part happens if you have multiple jobs or if your income is uneven. Your employer only knows about the wages they pay you, not what you earn elsewhere. If you earn $150,000 at one job and $100,000 at another, each employer may not withhold the surtax because neither one sees income above $200,000. When you file your tax return, you will owe the surtax on the $50,000 of combined income that exceeds the threshold. You can claim a credit for any surtax your employers did withhold, but you may still owe money at tax time.

This is why it matters to tell your tax preparer or accountant about all your income sources. They can help you figure out whether you will owe the surtax and whether you should adjust your withholding during the year.

How the investment income surtax works

The 3.8% surtax on investment income applies to certain types of income: capital gains, dividends, interest, rental income, and income from businesses that are not your main job. It only applies to the amount of investment income that, combined with your wages and other income, exceeds the threshold.

For example, if you are single and earn $180,000 in wages, you have $30,000 of "room" before hitting the $200,000 threshold. If you also have $50,000 in capital gains that year, only $20,000 of those gains are subject to the 3.8% surtax. The other $30,000 is not, because it falls within your threshold.

You do not pay this surtax when you sell an investment. Instead, you report it on your tax return when you file. Your tax preparer or the tax software you use should calculate it automatically if you report all your income sources.

Who does and does not owe the surtax

You owe the surtax only if your income exceeds the threshold for your filing status. Many people who are retired do not reach these thresholds, especially if they live on Social Security, pensions, and modest withdrawals from savings. Social Security income does not count toward the threshold, and neither do distributions from traditional IRAs or 401(k)s — only the income you earned during your working years counts.

However, if you have substantial investment income, rental property, or a part-time job in retirement, you may owe the surtax. Some retirees are surprised to learn that selling a home at a large profit can push them over the threshold in that one year. Others find that required minimum distributions from retirement accounts, combined with other income, trigger the surtax.

If you are married and file jointly, both spouses' income counts toward the $250,000 threshold. If one spouse earns $180,000 and the other earns $80,000, your combined income is $260,000, and you owe the surtax on the $10,000 that exceeds the threshold.

What happens to the surtax money

The surtax revenue goes into the Medicare Hospital Insurance Trust Fund, which pays for Medicare Part A (hospital insurance). It does not create a separate account for you or affect how much Medicare you receive. Your Medicare benefits are based on your age, your work history, and whether you have disabilities — not on how much surtax you paid.

The surtax was designed to help shore up the Hospital Insurance Trust Fund as more people became may be able to access for Medicare. The fund pays for hospital stays, skilled nursing care, hospice, and home health services. Without the surtax, the fund would have faced a shortfall sooner.

How to report the surtax on your tax return

If you are an employee and your employer withheld the surtax, it will appear on your W-2 form in box 6. When you file your tax return, your tax software or preparer will use this information to calculate what you owe.

If you are self-employed, you report the surtax on Schedule SE (Self-Employment Tax) and Form 8960 (Net Investment Income Tax). These forms calculate how much of your income is subject to the surtax and add it to your total tax bill.

If you have investment income, you report it on Schedule D (for capital gains), Schedule B (for interest and dividends), or Schedule E (for rental income). Form 8960 then calculates the 3.8% surtax on the portion of that income that exceeds your threshold.

If you think you will owe the surtax, you can make estimated tax payments during the year to avoid a large bill at tax time. Talk to a tax preparer or accountant about whether this makes sense for your situation.

Questions to ask your tax preparer or accountant

If your income is close to the threshold or you have multiple income sources, it is worth having a conversation with someone who knows your full financial picture. Here are some questions to ask:

  • Will I owe the Medicare surtax this year based on my income?
  • If I have multiple jobs or self-employment income, how should I handle withholding to avoid owing money at tax time?
  • If I am planning to sell an investment or a home, will that push me over the surtax threshold?
  • Are there any legal ways to reduce my income or defer it to a later year to avoid the surtax?
  • Should I make estimated tax payments during the year?

Frequently Asked Questions

Does Social Security count toward the Medicare surtax threshold?

No. Social Security benefits do not count as income for the purpose of calculating the surtax threshold. However, if you have other income — wages, self-employment income, or investment income — that income does count. Some retirees are surprised that a large capital gain or a year of high rental income can trigger the surtax even though their Social Security stayed the same.

Can I avoid the surtax by spreading my income across multiple years?

Sometimes, but not always. If you are selling an investment or a home, you might be able to time the sale to fall in a year when your other income is lower. Talk to a tax preparer or accountant before you make the sale. They can model different scenarios and help you understand the tax impact.

What if I disagree with the surtax amount on my tax return?

If you believe your tax return is wrong, you can file an amended return (Form 1040-X) within three years. You will need to show your work — all your income sources, your filing status, and the calculation of the surtax. If the IRS disagrees with your amended return, they will send you a notice. You can then appeal or request a hearing.

Does the surtax explore to disability or survivor benefits?

No. Social Security disability benefits and survivor benefits do not count as income for the surtax threshold, just as retirement benefits do not. However, if you have other income that exceeds the threshold, you will owe the surtax on that income.

Will the surtax threshold ever increase?

The thresholds are set by law and do not automatically adjust for inflation. Congress would have to pass new legislation to change them. As inflation continues and wages rise, more people may find themselves subject to the surtax even if their real income (adjusted for inflation) has not changed much.