Kelly Schedule Calculator
Updated November 2026 · Free · No sign-up
Calculate the Kelly schedule (firefighter 24/48) — The firefighter Kelly pattern: 24 hours on, 48 hours off, repeating every 3 days (9-day variants add a Kelly day off). See your average weekly hours, annual hours, and the next weeks of the rotation from any start date.
Quick answer: The Kelly Schedule runs a 3-day cycle with 1 shifts of 24 hours — averaging 56.0 hours/week (2920 hours/year) across 3 crews for continuous coverage.
The Pattern
The firefighter Kelly pattern: 24 hours on, 48 hours off, repeating every 3 days (9-day variants add a Kelly day off). Four numbers define it:
| Cycle length | 3 days | Shifts per cycle | 1 x 24h |
| Average week | 56.0 hours | Annual hours | ~2920 |
| Crews for 24/7 | 3 | Typical users | fire departments, EMS |
Worked Example
At $28/hour, the 56.0-hour average week grosses about $1,568/week — but pay varies BY WEEK with the rotation: weeks containing more shifts cross 40 hours and trigger overtime under weekly-OT rules, while light weeks run short. Many employers average or use period-based agreements; check how yours handles the heavy weeks.
Strengths and Trade-offs
Works well: two full recovery days after every tour; only ~10 tours a month; side-work friendly.
Watch for: the 56-hour average week is built in (fire-service FLSA rules use 212-hour/28-day thresholds instead of 40-hour weeks), and 24-hour tours include night interruptions. Night blocks also trigger night differentials where policy provides.
Overtime and Pay-Period Mechanics
Fixed-cycle schedules interact awkwardly with weekly overtime laws: a 3-day cycle does not align with 7-day workweeks, so some weeks exceed 40 hours even though the AVERAGE is 56.0. US employers handle it with premium built into rates, period agreements, or straight OT payment on heavy weeks; California daily rules add 1.5x past 8 hours (2x past 12) on every 24-hour shift unless an alternative workweek was adopted — see the California overtime calculator.
Living on This Rotation
Sleep research favors forward rotation and consistent blocks; the long off-stretches are this pattern’s reward — plan them like mini-vacations rather than recovery-only time. Swaps should trade like-for-like blocks to keep the cycle (and the pay averaging) intact. For planning days off around the rotation, the cycle preview below maps any month.
Frequently Asked Questions
What is the Kelly schedule (firefighter 24/48)?
The firefighter Kelly pattern: 24 hours on, 48 hours off, repeating every 3 days (9-day variants add a Kelly day off). It averages 56.0 hours/week over the 3-day cycle.
How many hours a year is this schedule?
About 2920 hours — 1 shifts x 24 hours per 3-day cycle, across 365 days.
Does this pattern trigger overtime?
Weeks with more shifts than average can exceed 40 hours even though the cycle averages 56.0 — weekly-OT jurisdictions owe premiums on those weeks unless a lawful averaging agreement applies.
How many crews does 24/7 coverage need?
3 crews rotate this pattern for continuous coverage — each crew offset within the cycle.
How does overtime work on 24/48?
Fire suppression uses the FLSA 7(k) exemption: OT starts past ~212 hours in a 28-day period rather than 40/week — the 56-hour average week is mostly straight time.
✓ Formula verified • Last updated: November 3, 2026