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W-2 Box 6: Medicare Tax Withheld (2025)

Updated October 17, 2026. Quick answer: Box 6 of Form W-2 shows the employee Medicare tax withheld, including any Additional Medicare Tax. The Instructions for Employee on the form say the amount includes the 1.45% Medicare tax on the Medicare wages in box 5 plus the 0.9% Additional Medicare Tax above $200,000. The box 5 instruction points you to Form 8959.

Related reading on this site: Form 8959 Additional Medicare Tax.

What box 6 reports

The employer instructions say: “Enter the total employee Medicare tax (including any Additional Medicare Tax) withheld.” “Do not include your share.” So the box holds only the employee side, and it is a withheld tax amount, not a wage amount. The wage amount that the tax is measured on is in box 5, described on the box 5 page.

As with the other tax boxes, the year is limited: “Include only tax withheld for 2025 wages and tips.” If the employer paid the employee share rather than deducting it, the same paragraph sends the employer to a separate set of rules. This page is the box 6 explainer, and the rest of boxes 1 to 8 are laid out in the W-2 boxes 1 to 8 guide.

What the employee copy says is inside box 6

The Instructions for Employee give the breakdown in one sentence: “This amount includes the 1.45% Medicare tax withheld on all Medicare wages and tips shown in box 5, as well as the 0.9% Additional Medicare Tax on any of those Medicare wages and tips above $200,000.” Read plainly, box 6 is two things added together: a regular Medicare tax on every dollar in box 5, and an additional tax on the part of box 5 that is above $200,000.

The employer instructions describe the second part from the withholding side: “In addition to withholding Medicare tax at 1.45%, an employer is required to withhold a 0.9% Additional Medicare Tax on any Federal Insurance Contributions Act (FICA) wages or Railroad Retirement Tax Act (RRTA) compensation it pays to an employee in excess of $200,000 in a calendar year.” And one detail is aimed at employees specifically: “Additional Medicare Tax is imposed only on the employee.” “There is no employer share of Additional Medicare Tax.”

An illustration of the arithmetic

As an illustration, not an IRS example, and taking the sentence on the employee copy at face value: suppose box 5 shows $210,000. The regular part is $210,000 × 1.45% = $3,045. The part of box 5 above $200,000 is $210,000 minus $200,000 = $10,000 and $10,000 × 0.9% = $90. Added together, $3,045 + $90 = $3,135 would be the box 6 figure on those assumptions.

The reason to run the numbers is to see whether the box 6 on your form is in the right neighborhood for the box 5 on your form. If box 5 is $200,000 or less, the sentence on the employee copy describes only the regular part. The Additional Medicare Tax and how it is figured at filing time are covered on the Additional Medicare Tax page.

Form 8959 and your return

The Instructions for Employee deal with Form 8959 under box 5, and it belongs next to box 6 in your reading of the form: “You may be required to report this amount on Form 8959.” “See the Form 1040 instructions to determine if you are required to complete Form 8959.” The wording is about the box 5 amount, so the form to read for the filing rules is the one the sentence names.

For how a Form W-2 flows into the return, see the Form 1040 page. Box 6 is also the box where uncollected Medicare tax is kept out. The box 12 instructions for code B say “Do not include this amount in box 6.”, which refers to Medicare tax on tips that the employer could not collect.

Why box 6 does not track box 1

The employee copy ties box 6 to box 5, not to box 1: it speaks of the tax withheld on “all Medicare wages and tips shown in box 5”. So when you compare box 6 with box 1, you are comparing a tax with a different wage measure. The three wage boxes are compared on the box 1 vs box 3 vs box 5 comparison, and box 1 is described on the box 1 page.

The dollar threshold works the same way. Two employees with the same box 1 can have different box 6 numbers if their box 5 amounts differ, because the additional tax in the quoted sentence depends on the Medicare wages and tips above $200,000.

Edition and box numbers

The primary read for this page is the 2025 edition of Form W-2, the Wage and Tax Statement an employee receives in early 2026 for tax year 2025. That includes the Notice to Employee and the Instructions for Employee printed on the copies, together with the 2025 General Instructions for Forms W-2 and W-3. The form itself is headed “Wage and Tax Statement 2025”. The 2026 edition was the one irs.gov served as current on 2026-10-17, and it was read side by side for comparison. Box 6 reads the same in both editions apart from the year. The 2026 instructions say “Enter the total employee Medicare tax (including any Additional Medicare Tax) withheld.” and the 2026 form’s Instructions for Employee repeat the breakdown: “This amount includes the 1.45% Medicare tax withheld on all Medicare wages and tips shown in box 5, as well as the 0.9% Additional Medicare Tax on any of those Medicare wages and tips above $200,000.” Check the tax year printed on the form you received, because the box numbers on this page are the ones on the 2025 and 2026 forms and your copy may be a different year.

Common mistakes

  • Treating the whole box 6 amount as the regular 1.45% tax. The form says it “includes the 1.45% Medicare tax” and also the Additional Medicare Tax.
  • Skipping Form 8959 without checking. The form says “You may be required to report this amount on Form 8959.”
  • Expecting a share from the employer to show up. The instructions say “There is no employer share of Additional Medicare Tax.”

Related: the Additional Medicare Tax page, Form 1040, the 2025 tax brackets, and self-employment tax.

Sources

Read from the IRS documents linked above on October 17, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.

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