W-2 code TT: Fluctuating workweek
Short answer: Under the fluctuating workweek method the salary pays for every hour worked, so the regular rate changes each week (salary ÷ hours worked) and code TT is half of it for each hour over 40.
Example
A $600 salary and 50 hours gives a $12 regular rate and code TT of 0.5 × $12 × 10 = $60. A 44-hour week gives $13.636 and $27.27; the regulation's own example shows $27.28 because it rounds the rate first.
A $600 salary and 50 hours gives a $12 regular rate and code TT of 0.5 × $12 × 10 = $60. A 44-hour week gives $13.636 and $27.27; the regulation's own example shows $27.28 because it rounds the rate first.
The rules
- Regular rate = (salary + other pay that belongs in the rate) ÷ hours worked that week (29 CFR 778.114).
- Each workweek stands alone; hours are never averaged (FS-2026-13 Q13).
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
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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Other situations
- Double time
- State daily overtime (California and others)
- Tipped employees
- Salaried non-exempt employees
- Nondiscretionary bonuses
- Piece-rate and day-rate pay
- Hospitals (8/80) and police or fire (7(k))
- Public-sector comp time
- Exempt employees and owners
- Weeks paid in the next year
- Fixing a wrong code TT amount (W-2c)