What Does Box 12 Code N Mean on a W-2?
Uncollected Medicare tax on group-term life insurance. What it means, whether it is taxable, and what to do with it.
By the Easy Guides Editorial Team · Updated for 2026
Box 12 Code N is uncollected medicare tax on group-term life insurance.
What Code N means
Medicare tax your former employer could not collect on group-term life insurance coverage over $50,000. Like Code M, it only appears for former employees.
Does Code N affect my taxes?
You owe it, and it was not withheld from a paycheck because there were no more paychecks.
What to do about it
Report it with your return as the Form 1040 instructions direct. It usually appears alongside Code M.
Where to find Code N on your W-2
Look at box 12, in the middle-right of the form. It has up to four lines, labelled 12a, 12b, 12c and 12d. Those letters are only line labels. The code you want is the small letter or pair of letters printed next to the amount, and it will read N. If you have more than four entries, your employer issues a second W-2 to carry the rest.
Not the code you were looking for? The full box 12 code list covers every letter, and the W-2 box decoder explains every box on the form.