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The ACGME limits that shape 24-hour call
Section 6 of the ACGME Common Program Requirements sets the clinical and educational work hour limits for US residency programs. For a call schedule built around 24-hour shifts, these are the ones you will check most often:
| Section | What it says |
|---|---|
| 6.20 | No more than 80 hours per week, averaged over four weeks, including in-house work, clinical work done from home and all moonlighting. |
| 6.21 | Residents should have eight hours off between scheduled work periods. |
| 6.21.a | At least 14 hours free of clinical work and education after 24 hours of in-house call. |
| 6.21.b | At least one day in seven free of clinical work and required education, averaged over four weeks. At-home call cannot be assigned on these days. |
| 6.22 / 6.22.a | No more than 24 hours of continuous scheduled clinical assignments, plus up to four hours for transitions of care and education, with no new patient care in that time. |
| 6.27 | In-house call no more often than every third night, averaged over four weeks. |
| 6.28 | Time spent on patient care during at-home call counts toward the 80 hours; at-home call is not limited to every third night but must respect the one-day-in-seven rule. |
Two details from the FAQ appended to the requirements trip up many schedules:
- Averaging is per rotation, not rolling. You average over a four-week period, a month, or the rotation if it is shorter. Vacation and leave days are removed from both the numerator and the denominator. A heavy block cannot borrow from a light one.
- A day off is a continuous 24-hour period. The FAQ says the day off should ideally be a calendar day and must not regularly fall on a post-call day. So the post-call day after a 24 usually does not count as one of the four days off.
Anatomy of one 24
Map one call on a timeline before you build a month of them. Say a resident starts in-house call at 07:00 on Monday:
- 07:00 Tuesday: the 24 hours of scheduled clinical assignment end.
- Up to 11:00 Tuesday: up to four more hours for handoffs and education, with no new patients.
- 14 hours free: the FAQ says the 14 hours start when the resident actually finishes all required work. If they leave at 11:00, they are free until at least 01:00 on Wednesday.
In practice that means Tuesday is gone, and the resident is next scheduled on Wednesday morning. Each 24 uses two calendar days, and the post-call day must have nothing on it: no clinic, no didactics, no "quick" procedure list. Put a visible "post-call" marker on the schedule so nobody books over it.
q3 or q4: run the hour arithmetic
The every-third-night limit is a ceiling, not a target. Here is what different call frequencies do to hours over a 28-day block. The assumptions are deliberately simple: every call runs the full 28 hours (24 + 4), every non-call working day is 10 hours, the post-call day has no work, and the resident gets exactly four days off.
| Pattern | Calls | Call hours | Regular days | Regular hours | Average per week |
|---|---|---|---|---|---|
| q3 (maximum) | 9 | 252 | 6 | 60 | 78 |
| q4 | 7 | 196 | 10 | 100 | 74 |
| q5 (approx.) | 6 | 168 | 12 | 120 | 72 |
| q7 | 4 | 112 | 16 | 160 | 68 |
How the rows add up: 28 days minus the call days, minus the same number of post-call days, minus 4 days off, gives the regular working days. For q3, that is 28 − 9 − 9 − 4 = 6 regular days, and (252 + 60) ÷ 4 = 78 hours a week. That is legal, but it leaves two hours a week of margin. One late sign-out per week, or one extra conference, and the block is over 80. q4 gives you more room, and anything less frequent gives more again.
A fair split, step by step
Equal totals are only the start. Residents remember which calls they had. Count these separately:
- Weekend 24s (Saturday and Sunday), because each one takes a weekend day and its post-call day.
- Friday 24s, because post-call lands on Saturday and the weekend is mostly gone.
- Holiday 24s, counted over the academic year, not the block.
- Spacing: the shortest gap between two calls for each resident.
Worked example: 7 residents, a 28-day block starting on Monday, one resident on 24-hour call each day. That is 28 calls, or exactly 4 each, which works out at q7 on average.
- Saturday and Sunday first. There are 8 weekend calls. Eight across seven people means one resident takes 2 and six take 1. Note who took the extra on the ledger, so it moves next block.
- Fridays next. There are 4. Give them to residents with only one weekend call, and never to someone on the following Saturday or Sunday.
- Weekdays last. Fill Monday to Thursday so everyone reaches 4, keeping at least three nights between calls.
| Group | Residents | Sat/Sun | Fri | Mon–Thu | Total |
|---|---|---|---|---|---|
| A | 1 | 2 | 0 | 2 | 4 |
| B | 4 | 1 | 1 | 2 | 4 |
| C | 2 | 1 | 0 | 3 | 4 |
Check the columns: 2 + 4 + 2 = 8 weekend calls, 4 Fridays, 2 + 8 + 6 = 16 weekday calls. Groups A and B carry two "heavy" calls (Friday to Sunday), group C carries one. Next block, group C's two residents go to the front of the queue for Fridays and weekends.
Protect golden weekends
The one-day-in-seven rule can be met with scattered single days, but the ACGME's own background text notes that the rule does not stop programs from giving a full weekend, or two consecutive days, off. Residents value these far more than a lone Tuesday. A practical rule: every resident gets at least one full weekend off per block, with no Friday call before it. Fix those weekends before placing any calls, the same way you lock in vacation.
Holidays and the yearly ledger
A month is too short to make holidays fair. Keep a list of the year's holidays, sort them by how much people care about them (Thanksgiving, Christmas and New Year usually top the list), and rotate them across the year. A common approach is to pair holidays: whoever works Thanksgiving is off Christmas, and the other group swaps. Record every holiday call on a running ledger that the whole program can see. Our guide on balancing weekend and holiday shifts has a full method, including weighted points.
Swaps without breaking the rules
Most violations happen after the schedule is published. A Friday swapped for a Sunday can create a call on consecutive nights, push someone over q3 for the block, or land a 24 on a promised day off. Re-check every swap against the same rules you used to build the schedule: spacing, post-call protection, the days off and the 80-hour average. Then update the counts. Our guide on leave and swaps has a short checklist.
Pre-publish checklist
- No resident has in-house call more often than every third night, averaged over the block.
- Every 24 is followed by a post-call day with nothing scheduled.
- Each resident has at least four true 24-hour days off per four weeks, not on post-call days.
- Projected hours stay comfortably under 80 per week, with leave removed from the calculation.
- Weekend, Friday and holiday calls are counted and published per resident.
- Your Review Committee has no stricter limit that you have missed.
For the general method behind a fair rota, see how to make a fair on-call schedule for residents. If you want a draft in a few seconds, the free call schedule generator runs in your browser and your data stays on your device.
Sources
- ACGME Common Program Requirements (Residency), 2026, with FAQs: sections 6.20–6.28, the averaging FAQ, the 14-hour FAQ and the day-off FAQ.
- ACGME, Review and Comment: the major revision of the Common Program Requirements, open for comment until 22 October 2026.
Let the counts take care of themselves
FasterShift is an AI-powered scheduler for residency programs and hospital teams. You write rules like "no one on call more than every fourth night" or "share weekend 24s evenly", and it drafts a call schedule with the counts per resident shown next to it. Try FasterShift free for 14 days — no card needed. After the trial, plans start from US$12 per team per month.
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