W-2 code TT: Fixing a wrong code TT amount (W-2c)
Short answer: File and furnish Form W-2c as soon as you find the error, with the code and amount in both the previously reported and the correct box 12 fields. Employees can't deduct more than their W-2 shows, and Form 4852 can't replace it.
Example
A W-2 shows TT $1,200 but the week-by-week rebuild gives $1,480. Issue a W-2c with box 12 previously reported "TT 1200.00" and correct "TT 1480.00". The employee can then deduct $1,480 instead of $1,200.
A W-2 shows TT $1,200 but the week-by-week rebuild gives $1,480. Issue a W-2c with box 12 previously reported "TT 1200.00" and correct "TT 1480.00". The employee can then deduct $1,480 instead of $1,200.
The rules
- An employer that finds a code TT error must file Form W-2c and furnish it to the employee (FS-2026-13 Q11).
- Under-reported: the employee can use only the amount reported, unless corrected (FS-2026-13 Q20, Q22).
- Over-reported: only the amount actually paid counts (FS-2026-13 Q21). Form 4852 is not valid (Q23).
- W-2c box 12: enter both the code and the amount in both fields (2026 W-2/W-3 instructions).
Work it out for your payroll
The free code TT calculator does this per workweek for one employee or a whole payroll CSV, with bonuses spread back and weeks split by pay date. It runs in your browser.
The free code TT calculator does this per workweek for one employee or a whole payroll CSV, with bonuses spread back and weeks split by pay date. It runs in your browser.
Whole payroll, offline? The W-2 Code TT Kit runs every employee in one file with no network access, plus CSV templates, the week-by-week audit trail and a 12-page guide to every rule.
Get the kit ($29, accountants $99)
Get the kit ($29, accountants $99)
Sources
- IRS FS-2026-13: Qualified overtime compensation FAQs (August 2026)
- IRS: 2026 General Instructions for Forms W-2 and W-3
Not tax or legal advice. Facts checked 27 Oct 2026 against the IRS FAQs (FS-2026-13) and the FLSA regulations.
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