Your Medicare tax went up because the wage base — the amount of income subject to the tax — increased, or because you earned more than you did the previous year.

Medicare tax is calculated as a percentage of your wages. The percentage itself stays the same year to year, but the wage base — the maximum amount of income that gets taxed — rises each January to match inflation. In 2024, for example, the wage base increased from the previous year's amount. If you earned more than that new threshold, the additional income above it is taxed at the Medicare rate, which is why your withholding went up even if your pay rate did not.

The other common reason is straightforward: you earned more money. If you received a raise, worked more hours, took a second job, or had income from self-employment, your Medicare tax obligation increases proportionally. Your employer withholds Medicare tax from each paycheck, so higher earnings mean higher withholding.

Key Takeaways

  • The Medicare wage base increases each year in January to account for inflation, which means more of your income is subject to the tax.
  • If you earned more than you did the previous year — through a raise, extra hours, or additional income — your Medicare tax withholding will be higher.
  • Self-employed people pay both the employee and employer portions of Medicare tax, which is why their tax can jump noticeably year to year.
  • High earners pay an additional 0.9% Medicare tax on income above a certain threshold, which also increased for 2024.

How the Medicare wage base works

Medicare tax is 2.9% of your wages: your employer withholds 1.45% and pays 1.45%. Unlike Social Security tax, which stops once you hit an annual wage cap, Medicare tax has no upper limit — theoretically, all your income is subject to it. However, the amount of income that counts toward Medicare changes each year.

The Social Security Administration announces the new wage base every October for the following year. The 2024 wage base was higher than 2023's, which was higher than 2022's. This adjustment happens automatically; you do not need to do anything. Your employer's payroll system uses the new figure starting in January, and your withholding adjusts accordingly.

If you changed jobs during the year, moved to a state with different tax rules, or had a significant change in income, your withholding may have been recalculated mid-year as well. This is separate from the wage base increase but can also explain a jump in your Medicare tax.

The additional Medicare tax for higher earners

If you earned above a certain income threshold in 2024, you owe an additional 0.9% Medicare tax on the amount over that threshold. For single filers, the threshold is $200,000; for married couples filing jointly, it is $250,000. These thresholds do not adjust for inflation, so more people reach them each year as wages rise.

Your employer is required to withhold this additional tax once your year-to-date wages exceed the threshold. If you have multiple jobs or a spouse who also works, you may owe this tax even if neither of you individually crosses the threshold. In that case, you would claim a credit when you file your tax return.

Self-employed workers and Medicare tax

If you are self-employed, you pay both the employee and employer portions of Medicare tax — 2.9% total, or 3.8% if you are over the income threshold. This is why self-employed people often see a larger jump in Medicare tax year to year. You calculate and pay it yourself when you file your tax return, usually through estimated quarterly tax payments.

Self-employed income includes net profit from your business, rental income, and certain other sources. The wage base increase affects you the same way it affects employees, but because you are paying both sides of the tax, the dollar amount is roughly double what an employee would pay on the same income.

What to check on your pay stub

Your pay stub should show the Medicare tax withheld for that pay period and your year-to-date total. Compare your year-to-date Medicare withholding to last year's at the same point in the year. If it is higher and your pay rate has not changed, the wage base increase is the likely reason.

If the increase seems much larger than you would expect, check whether you crossed the additional 0.9% threshold or whether your employer recalculated your withholding mid-year. You can also contact your employer's payroll department to ask whether they adjusted your withholding for any reason.

Planning for next year

The Medicare wage base and the additional Medicare tax threshold are announced each October by the Social Security Administration. If you are self-employed or have irregular income, knowing the new figures helps you plan your estimated tax payments. You can find the current year's figures on the Social Security Administration website or ask your tax preparer.

If you are concerned that too much or too little is being withheld, you can adjust your W-4 form with your employer. This does not change your actual tax obligation, but it changes how much is taken from each paycheck, which can help you avoid a large bill or refund at tax time.

Frequently Asked Questions

Does Medicare tax have a cap like Social Security tax does?

No. Social Security tax stops once you reach the annual wage base, but Medicare tax continues on all your income with no upper limit. However, if you earn above the threshold for the additional Medicare tax, that extra 0.9% applies only to income above the threshold.

Why did my Medicare tax go up if my salary stayed the same?

The wage base increased in January. More of your income is now subject to Medicare tax, so even at the same salary, your withholding is higher. This happens every year and is not related to your individual earnings.

Can I reduce my Medicare tax withholding?

You cannot reduce the actual tax you owe, but you can adjust your W-4 to change how much is withheld from each paycheck. Keep in mind that you will owe the full amount at tax time if you under-withhold. Talk to your employer's payroll department or a tax preparer before making changes.

If I have two jobs, do I pay the additional 0.9% Medicare tax twice?

You may have it withheld from both jobs if your combined income crosses the threshold. When you file your tax return, you can claim a credit for the extra withholding from the job that did not reach the threshold on its own. Your tax preparer can help you sort this out.