Shift Differentials, On-Call, and Call-Back Pay

General information, not legal or tax advice. Checked October 2026. Sources are listed at the end.

Healthcare runs around the clock, so most healthcare payrolls pay more than one rate. Differentials, on-call stipends, call-back guarantees, and pick-up shift bonuses help you cover hard shifts, but each one has its own rule for whether it counts as hours worked and whether it raises the overtime rate.

Shift differentials

A shift differential is extra pay for working a less desirable shift: nights, evenings, weekends, or holidays. Neither federal nor Arizona law requires one, but once you pay it, it's part of the employee's regular rate under 29 CFR 778.207. That means it raises the overtime rate in any week the employee works over 40 hours.

Differentials can be a flat amount per hour ($3 more on nights), a percentage (10% more on weekends), or a per-shift amount. Each works, as long as payroll adds the differential into the regular rate before figuring overtime.

Worked example: differential plus on-call stipend

Paying overtime at $60 (time and a half of the $40 base) would have shorted her $8.09 this week. Small per check, but it repeats every week for every nurse on nights.

On-call time

Whether on-call time is paid depends on how restricted it is, under 29 CFR 785.17:

• On call at your facility, or required to stay so close that the employee can't use the time for their own purposes: that's work time, paid and counted toward overtime.
• On call at home with a phone, free to go about their day within a reasonable response time: generally not work time. But time spent answering calls, giving phone advice, charting, or logging in remotely is work time.
• Frequent calls can turn unpaid on-call time into paid time if the employee can't use the time effectively for themselves.

An on-call stipend, a flat amount for being available, is part of the regular rate for the week it's earned.

Call-back pay

Many practices and facilities guarantee a minimum when an employee is called back after leaving, such as two hours of pay even if the call takes 45 minutes. Under 29 CFR 778.221, the part of a call-back guarantee that's more than pay for time actually worked can generally be left out of the regular rate, as long as call-backs are infrequent and not prearranged. The time actually worked on a call-back still counts toward the 40.

Pick-up shift, retention, and attendance bonuses

Bonuses employees are promised in advance for meeting a condition are non-discretionary and go into the regular rate. That includes pick-up or "critical shift" bonuses, perfect attendance bonuses, and retention bonuses paid for staying a set period. When a bonus covers more than one workweek, the overtime owed on it has to be spread back across the weeks it was earned.

Truly discretionary bonuses, where you decide both whether to pay and how much at the end of the period with no promise in advance, can be left out.

Holiday pay

Neither federal nor Arizona law requires holiday pay. If you pay a holiday premium of at least time and a half for hours actually worked on a holiday, federal rules generally let you leave the premium out of the regular rate and credit it toward overtime owed that week. A smaller holiday bump, such as $2 more an hour, is treated like a differential and goes into the regular rate.

Setting up payroll for multiple rates

• Set up each differential as its own earnings code, so it flows into the regular rate automatically
• Record on-call time and call-back time separately from regular hours
• Keep the bonus terms in writing, with the period each bonus covers
• Test a sample week with a differential and overtime before your first live payroll

For the overtime rules themselves, including the 8-and-80 system, see healthcare overtime rules in Arizona.

Shift pay questions

Do shift differentials count toward overtime?

Yes. Night, weekend, and other shift differentials are part of the regular rate, so they raise the overtime rate. Paying overtime on the base wage alone is one of the most common healthcare payroll errors.

Is on-call time paid?

It depends on how restricted the employee is. Time spent on call at your facility, or so restricted that the employee can't use it for personal purposes, is work time. On-call time at home with a phone, free to go about their day, generally isn't, but time spent answering calls, charting, or coming in is.

Does an on-call stipend go into the regular rate?

Yes. Pay for being on call is part of the regular rate, so it raises the overtime rate for that week.

Does call-back pay go into the regular rate?

A guaranteed minimum for being called back, such as two hours of pay for a 45-minute call, can generally be left out of the regular rate to the extent it exceeds pay for time actually worked, if call-backs are infrequent and not prearranged. The time actually worked still counts toward overtime.

Is holiday pay required in Arizona?

No. Neither federal nor Arizona law requires holiday pay. If you pay a holiday premium of at least time and a half for hours worked on a holiday, it can generally be left out of the regular rate and credited toward overtime.

Sources

• U.S. Department of Labor: overtime pay
• 29 CFR 778.207: shift differentials and other premiums
• 29 CFR 785.17: on-call time
• 29 CFR 778.221: call-back pay
• 29 CFR 778.223: pay for non-productive hours