Shift differential calculator

A flat differential adds a fixed amount per hour, independent of your base rate. If your differential is +$4.00/hr and you work 8 differential-eligible hours, that's an extra $32.00 no matter what your base rate is.

A percentage differential adds a percentage of your base rate instead. At +10% on a $40/hr base rate, each differential-eligible hour earns an extra $4.00 — but at +10% on a $25/hr base rate, it's only an extra $2.50. Percentage differentials scale with pay grade; flat differentials don't. Neither is inherently better — it depends on what your employer has agreed to pay.

Either way, the formula for the extra pay is the same shape: eligible hours × (flat amount, or base rate × percent).

Some shifts qualify for more than one differential at the same time — for example, a Saturday night shift can be both a night shift and a weekend shift. Employers handle the overlap in one of two common ways:

This calculator lets you choose which policy to model, because assuming one universally would make the estimate wrong for roughly half of employers. If you're not sure which applies to you, your pay policy or HR handbook should say.

When a differential only covers part of a shift — say, the Saturday portion of a Friday-night shift — an unpaid break could in principle fall entirely inside that portion, entirely outside it, or somewhere in between, and each would change the "actual" differential-eligible hours. Rather than guess where your break happened, this calculator spreads the break proportionally across the whole shift, so every segment loses the same fraction of its hours.

Worked example: a Friday 19:00 → Saturday 07:00 shift has a 60-minute unpaid break and a $12/hr weekend differential. The shift spans 7 hours of Saturday out of 12 total, so the weekend-eligible hours are 7 × (11 paid ÷ 12 scheduled) = 6.42 hours, for a differential of about $77. If the break were known to fall entirely on Friday, the true weekend-eligible time would be the full 7 hours ($84); entirely on Saturday, it would be 6 hours ($72). The calculator's proportional estimate of $77 sits between those two real possibilities — a deliberate, disclosed approximation, not a bug.

A related estimate: a shift that crosses a daylight saving time change is paid for its full scheduled duration rather than the shorter or longer elapsed time — see the night shift pay calculator for that policy in detail.

Because differentials are generally part of your regular rate for overtime purposes, this calculator estimates overtime using this shift's own effective rate — base earnings plus differentials, averaged over its paid hours — rather than any pay from a prior week, which it has no way to know. That keeps the estimate self-contained to the shift you're calculating, but real payroll overtime calculations that look at a full workweek can land on a different number.

There's no federal requirement to pay a shift differential at all, let alone a standard rate for one — it's set by your employer, and sometimes by a union contract. That's why this calculator treats the differential amount, type, window and stacking rule as inputs rather than assumptions. For night-specific detail, see the night shift pay calculator . Nurses evaluating charge, preceptor or specialty pay on top of a night or weekend differential may find the nurse shift pay calculator more directly useful.