What Does Box 12 Code F Mean on a W-2?
408(k)(6) contribution — what it means, whether it's taxable, and what to do with it.
By the Easy Guides Editorial Team · Updated for 2026
Code F in Box 12 of your W-2 means 408(k)(6) contribution. Tax treatment: Pre-tax (already excluded).
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
Box 12 has up to four slots — labeled 12a, 12b, 12c, and 12d. Each slot shows a letter code and a dollar amount. The 12a–12d labels are just line numbers; the actual code is the small letter next to the money. So "12a: F 5,000" means Code F with a $5,000 amount. When you file, enter the code and amount exactly as shown.