Updated October 17, 2026. Quick answer: Box 5 of Form W-2 shows the wages and tips subject to Medicare tax. The instructions say there is no wage base limit for Medicare tax, so box 5 can be larger than box 3 for higher earners. The Instructions for Employee on the form say you may be required to report this amount on Form 8959.
More IRS forms and schedules for individual filers, read line by line: Form 4137 instructions.
Related reading on this site: Form 8959 Additional Medicare Tax.
What box 5 reports
The employer-side instructions define the box by comparing it with social security wages: “The wages and tips subject to Medicare tax are the same as those subject to social security tax (boxes 3 and 7) except that there is no wage base limit for Medicare tax.” The instruction to the employer is “Enter the total Medicare wages and tips in box 5.”
For what counts as a payment to report, the box 5 instruction points back to the box 3 list: “payments to report in this box.” That is why a deferral that is excluded from box 1 shows up here. The box 3 side is on the box 3 page, and the rest of the form is in the W-2 boxes 1 to 8 guide.
No wage base limit: why box 5 can be larger than box 3
The box 3 instructions cap the social security figure, and box 5 has no such cap. The instructions work an example: “You paid your employee $199,750 in wages.” “Enter in box 3 (social security wages) 176100.00, but enter in box 5 (Medicare wages and tips) 199750.00.” “There is no limit on the amount reported in box 5.”
Where wages stay under the base, the two boxes match: “If the amount of wages paid was $176,100 or less, the amounts entered in boxes 3 and 5 will be the same.”
A labelled illustration, not an IRS example: using the figures in the instructions’ own example, box 5 minus box 3 is $199,750 minus $176,100 = $23,650. That is the part of the pay above the 2025 base that is counted for Medicare and not for social security. The base for later years is on the social security wage base page.
Box 5 compared with box 1
Box 5 follows the Medicare rules rather than the box 1 rules. The box 1 instructions say “do not include elective deferrals (such as employee contributions to a section 401(k) or 403(b) plan) except section 501(c) (18) contributions”, while the box 3 instructions, which box 5 follows, say to report in box 3 elective deferrals to certain qualified arrangements and to retirement plans described in box 12 (codes D, E, F, G, and S) “even though the deferrals are not includible in box 1”. So for a worker with a 401(k) deferral and pay below the base, box 5 equals box 3 and both exceed box 1. That relationship is shown with numbers on the box 1 page, and the codes that label the deferral are covered on the box 12 vs box 1 page.
Other items counted in box 5
Some pay is counted in box 5 on a later schedule than it is earned. The instructions say amounts deferred under certain nonqualified plans “must be included in boxes 3 and/or 5 as social security and/or Medicare wages”. Group-term life insurance is another item: the instructions say the employer “must include in boxes 1, 3, and 5” the cost above the coverage threshold.
Tips are counted too: “Be sure to enter tips that the employee reported even if you did not have enough employee funds to collect the Medicare tax for those tips.” That means box 5 can include tips even if the Medicare tax on them was not fully collected from your paycheck. Tips on the form are covered on the box 7 page and the box 8 page.
Government employees get a special case: “If you are a federal, state, or local governmental agency with employees paying only Medicare tax, enter the Medicare wages in this box.” This applies to government employers whose employees pay only Medicare tax.
Where box 5 goes and the Form 8959 note
Unlike box 1, box 5 does not go on the wages line. The Instructions for Employee say: “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.”
Form 8959 is the form for the Additional Medicare Tax, which is explained on the Additional Medicare Tax page. The Medicare tax actually withheld is box 6, and the form says that amount “includes the 1.45% Medicare tax withheld on all Medicare wages and tips shown in box 5”. Box 6 is covered on the box 6 page.
Edition and box numbers
The primary read for this page is the 2025 edition of Form W-2, the one an employee receives in early 2026 for tax year 2025. The printed form carries the line “Wage and Tax Statement 2025”, and the matching General Instructions for Forms W-2 and W-3 (2025) were read alongside it. The 2026 edition of the form and of the General Instructions was the current one irs.gov was serving on 2026-10-17, and both were compared. The box 5 definition and the Form 8959 note read the same in both editions. The only difference found in the box 5 text is the wage base in the example. The 2025 example reads “If the amount of wages paid was $176,100 or less, the amounts entered in boxes 3 and 5 will be the same.” The 2026 example reads “If the amount of wages paid was $184,500 or less, the amounts entered in boxes 3 and 5 will be the same.” Box 5 is box 5 in both editions. Check the tax year printed on the form you received, because the figures and wording on your copy come from that year’s edition, and the box numbers on your copy are the ones to follow.
Common mistakes
- Expecting box 5 to stop at the wage base. The instructions say “There is no limit on the amount reported in box 5.”
- Using box 5 as the wages line figure. The form sends box 1 to the wages line with “Enter this amount on the wages line of your tax return.” Box 5 is for Form 8959 if you are required to file it.
- Assuming a gap between box 3 and box 5 means an error. The instructions say “except that there is no wage base limit for Medicare tax”, so a higher box 5 on high pay is expected.
Related: the Additional Medicare Tax, the social security wage base, W-2 box 12 vs box 1, and Form 1040.
Sources
- General Instructions for Forms W-2 and W-3 (2025): IRS archived PDF (irs.gov)
- General Instructions for Forms W-2 and W-3 (2026): https://www.irs.gov/pub/irs-pdf/iw2w3.pdf
- Form W-2, Wage and Tax Statement (2025), with the Notice to Employee and Instructions for Employee: IRS archived PDF (irs.gov)
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.