Teenagers are cheap, keen and available after school, which is why cafes, shops and salons hire them. They are also the staff whose hours the law limits most tightly, and the limits quietly change which shifts they can take at all. We measured it.
For 14 and 15 year olds the federal rules are: work only between 7am and 7pm (9pm from June 1 to Labor Day); in a school week at most 3 hours on a school day and 18 hours; outside school at most 8 hours a day and 40 hours a week. States add work permits, break rules and tighter hours, and the stricter rule wins, so treat this as a floor.
The roster builder's invented seven-person cafe: 32 shifts, 235 hours to cover. Cleo and Eli are the two youngest on the team. Only their ages changed between runs, using the age: cell; everything else is the tool's defaults.
| Cleo and Eli | Shifts left open | Hours covered | Payroll | Cleo + Eli hours |
|---|---|---|---|---|
| No age set | 3 | 216 | $3,622 | 36 |
| Cleo 15, school weeks | 5 | 200 | $3,382 | 18 |
| Cleo 15 and Eli 14, school weeks | 7 | 184 | $3,168 | 0 |
| Both, summer | 3 | 216 | $3,632 | 32 |
In a school week neither teenager fits a single shift. The cafe's shifts run 6 to 14 and 14 to 22 and the limits stop work at 7pm and cap a day at 3 hours, so a whole 8-hour shift never fits inside what they may do. The two of them go from 36 hours to none and four more shifts go unfilled; the payroll falls only because the hours disappear. In summer the window widens to 9pm and the day to 8 hours, and most of it comes back. The lesson is not that teenagers are a bad hire. It is that a teenager needs short shifts built for them (a 3-hour 4pm to 7pm slot, or a weekend half-day) rather than a place in the adult rota.
This is one invented example, not a benchmark. The page applies the 3-hour school-day cap to every day in school mode, which is the cautious reading; the federal rule counts only school days, so for Saturdays use the summer setting or an off: cell for school hours.
Start from the legal window (7am to 7pm in term), then take away school hours and anything their parents have told you.
The after-school rush and weekend lunch are where a 3-hour shift helps most. Add them as separate shifts instead of trimming an adult shift.
Put an adult on every stretch a minor works. The roster builder flags any stretch where only people marked as minors are on shift.
Under the US Fair Labor Standards Act, 14 and 15 year olds may work only between 7am and 7pm (9pm from June 1 to Labor Day), for at most 3 hours on a school day, 18 hours in a school week, 8 hours on a non-school day and 40 hours in a non-school week. Many states are stricter and some require work permits, so check yours.
Add age: 15 (or age: 15 summer) to that person's row. The search then treats the limits above as hard rules, and any age under 18 also marks the person as someone who should not be alone on shift. Ages under 14 are refused.