What Does Box 12 Code F Mean on a W-2?
408(k)(6) contribution. 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 F is 408(k)(6) contribution.
What Code F means
These are rare, only older SARSEPs established before 1997 still use Code F. If you see it, treat it like any other pre-tax retirement deferral.
Does Code F affect my taxes?
A salary-reduction contribution to a SEP plan (a SARSEP). It's pre-tax and already excluded from your Box 1 wages.
Where to find Code F 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 F. 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.