24/48 Shift Calculator

A 24/48 is the most common career-fire rotation in the United States: you work a 24-hour shift, then you are off for 48 hours, and the cycle repeats without a break. Three platoons, usually called A, B, and C shift, rotate through the pattern so that exactly one platoon is on duty in the station every single day of the year.

Because the cycle is three calendar days long and each firefighter works one of those three days, the pattern is perfectly even. Line it up on a calendar and your on-duty days march forward by one slot every cycle: work Monday, off Tuesday and Wednesday, work Thursday, and so on. The calculator above phases the pattern to a real on-duty date you enter, so the dates it projects match your actual platoon rather than a generic template.

Over one three-day cycle you work a single 24-hour shift, which averages to 8 hours a day, or roughly 56 hours across a 7-day week. Annualized, a straight 24/48 with no reductions comes to about 2,920 hours a year. That average is the whole reason the schedule gets so much attention at contract time.

The number that matters most is the hours per work period. Fire departments do not measure overtime on a 40-hour week. Under the FLSA public-safety rules they declare a work period of up to 28 days, and for fire protection employees a 28-day period caps straight time at 212 hours. A 24/48 runs about 224 hours in that same 28 days, which is roughly 12 hours over the cap. In other words, about 12 hours of overtime are baked into every 28-day period whether or not anyone ever picks up an extra shift.

That built-in overtime is expensive, and it is also uneven, so many departments trim the average with a Kelly day: a scheduled day off that recurs every few tours to pull the hours back down. Drop one 24-hour shift about every eighth tour and the same 24/48 lands near 196 hours per 28-day period, comfortably under the 212-hour cap, and the average work week falls from about 56 hours toward 49.

Not every 24/48 department uses a Kelly day, and the ones that do phase it differently, so the built-in overtime, the reduction, or both can show up in your paycheck. The calculator lets you turn a Kelly day on, set the cadence your contract actually uses, and watch the FLSA position move in real time. If you want to model the Kelly day in more detail, the dedicated Kelly day calculator covers all four contract variations.

FLSA Section 7(k) is the public-safety exemption that lets fire and EMS employers measure overtime over a 7 to 28 day work period instead of a standard 40-hour week. The employer picks a work-period length and declares it; hours worked above the cap for that length are paid at the overtime rate. For a 28-day period the fire cap is 212 hours; shorter periods scale down from there, so a 14-day period caps at 106 hours and a 7-day period at 53.

On a straight 24/48 the scheduled hours sit above the cap, so the recurring schedule itself generates overtime. Add held-over calls, mandatory overtime, or picked-up shifts and the total climbs from there. The tool above shows the scheduled position for the work period you select, which is the floor; anything extra you actually work stacks on top of it.