California Daily Overtime Tax Deduction: Why the 9th Hour Does Not Count.

A field service technician outside Sacramento works four 10-hour days a week. Every one of those weeks his employer pays eight hours at time and a half, because California requires overtime after the eighth hour in a workday. He has been planning on the new federal overtime deduction covering it. His California daily overtime tax deduction on those weeks is zero. Not reduced, not phased out, zero, because the week never crossed 40 hours and the federal deduction only reaches overtime the Fair Labor Standards Act requires.

Section 7 of the Fair Labor Standards Act, codified at 29 U.S.C. §207(a), requires one and a half times the regular rate for hours worked over 40 in a workweek. It says nothing about how long a day runs. California Labor Code §510(a) requires time and a half after eight hours in a workday and after 40 hours in a workweek, double time after 12 hours in a day, and time and a half for the first eight hours on the seventh consecutive day of work. The two rules overlap only on the hours past 40. Section 225(c) defines qualified overtime compensation as overtime required under FLSA section 7 that is in excess of the regular rate, which leaves every state-only hour outside the deduction.

The second cut is bigger than most people expect. Only the excess over the regular rate qualifies, not the whole overtime hour. At a $45 regular rate an overtime hour pays $67.50, and the qualified piece is the $22.50 on top. When California double time kicks in past 12 hours in a day, the hour pays $90 and the qualified piece is still $22.50, because the FLSA requires only half the regular rate above straight time and the second $22.50 is state law. The IRS said this plainly in Fact Sheet FS-2026-01 on January 23, 2026: where an employer pays more than the FLSA requires, only the FLSA-required amount counts.

There is a wrinkle worth knowing if you run the payroll. Under California Labor Code §511 a work unit can adopt an alternative workweek schedule by two-thirds secret ballot, and a properly adopted 4/10 owes no daily overtime until the eleventh hour. So the shop that did the paperwork pays no daily premium and gives up no deduction, and the shop that did not pays eight hours of premium a week that produces nothing on the employee's return. The schedule that generates the most California overtime generates the least federal deduction.

Here is the technician's year. Same 10-hour days throughout, same $45 regular rate, and the only thing that changes is whether the week ran four days or five.

He was paid $9,180 of overtime premium and can deduct $4,500 of it, 49 cents on the dollar. The work was identical in both halves of the year. The federal test is the workweek, so the 26 weeks that stopped at 40 hours produced California overtime and no federal deduction, and the 20 weeks at 50 hours produced both.

Section 70202(c) of the 2025 tax act added §6051(a)(19) to the Code, which requires the W-2 to state the employee's total qualified overtime compensation. For 2026 that amount goes in Box 12 with code TT on the forms employees receive early in 2027, alongside code TP for qualified tips. Notice 2025-62, issued November 5, 2025, waived the §6721 and §6722 penalties for failing to break the figure out, but only for calendar year 2025. There is no relief for 2026, and the penalties apply per form on both the copy filed and the copy furnished.

In California the number payroll already has is the wrong one. The wage statement required by Labor Code §226 reports overtime the way the state computes it, daily premiums and double time included. Code TT wants the FLSA-required premium, computed week by week on hours over 40, at the FLSA regular rate. That rate is not the base hourly rate either. Under 29 U.S.C. §207(e) it takes in nondiscretionary bonuses, shift differentials, and most production pay, so a quarterly safety bonus raises the premium for the weeks it covers. If your provider is filling Box 12 by copying the overtime earnings line, the figure is too high, and an overstated code TT hands your employees a deduction they cannot support.

For the worker the mechanics are short. The deduction goes on Schedule 1-A (Form 1040), Part III, and it is available whether or not you itemize. Section 225(e) requires a joint return if you are married, so married filing separately gets nothing, and §225(d) denies the deduction unless your Social Security number is on the return. The phase-out in §225(b)(2) cuts $100 for every $1,000 of modified adjusted gross income above $150,000, $300,000 on a joint return, so a single filer at $200,000 keeps $7,500 of the $12,500. It hits zero at $275,000 single and $550,000 joint.

If you expect a real number, take it during the year instead of waiting on the refund. The 2026 Form W-4 lets you account for the expected deduction in the Step 4(b) deductions worksheet, the same lever I use for withholding across two jobs. That is worth filing when the deduction runs into the thousands and not worth the paperwork under about $1,000.

Calibrate the size before you plan around it. At a $45 regular rate, filling the $12,500 cap takes roughly 556 hours of work past 40 in a week, about 11 hours of federal overtime every week of the year. Most California hourly workers are nowhere near that, and the ones on daily-overtime-heavy schedules are furthest from it. I would not move anyone off a 4/10 to chase it, and an employer cannot convert state overtime into federal overtime, because the test is hours over 40 and nothing else. The same trap sits in Alaska, in Nevada for workers earning under one and a half times the minimum wage, and in Colorado past 12 hours in a day. Like the car loan interest deduction, this one is smaller in practice than its name suggests, and it expires after 2028 unless Congress extends it.