Only the FLSA half-premium belongs in Code TT. Payroll exports put the whole time-and-a-half there.
Correct Box 12 Code TT per employee
—
$
What your export writes into Box 12
—
$
Overstatement per W-2
—
$
Overstatement across the payroll
—
$
State-only premium correctly excluded
—
$
Deduction the employee may actually take
—
$
Deduction overclaimed from the wrong W-2
—
$
IRC 6721 + 6722 exposure
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$
Keep this audit: .csv export + a 2027-02-01 furnish alarm
Every figure above is free, unlimited, no key. The $60 key adds a different thing: a per-employee .csv you keep in the payroll file, and a browser alarm before the 2027-02-01 W-2 furnish date. $60 once · one licence key per person or team seat · Getting Box 12 wrong costs $340 under IRC 6721 plus $340 under IRC 6722 per W-2.
FLSA half-premium only Splits the one-half premium required by 29 USC 207 from the straight-time hours, because only that half is qualified overtime compensation under IRC 225.
State-only daily overtime excluded Daily overtime hours that a state (California 8+/day, Alaska, Nevada, Colorado) requires but the FLSA does not are not qualified overtime — they are removed from the Code TT figure.
Payroll export drift Shows what a payroll export writes into Box 12 when it maps the whole overtime gross, and the dollar overstatement per employee and across the company.
2026 deduction and phaseout Applies the $12,500 / $25,000 cap and the $100-per-$1,000 MAGI phaseout above $150,000 / $300,000 so you can see what the employee may actually deduct.
6721 + 6722 exposure Multiplies the affected headcount by both the information-return penalty and the payee-statement penalty, which apply separately to the same wrong form.
Furnish deadline Anchors the numbers to 2027-02-01, the date 2026 Forms W-2 must be furnished and filed, since January 31, 2027 falls on a Sunday.