Tallywell.

Night Shift Caffeine Calculator

Night work runs your caffeine and your sleep in the wrong order. This plans both: when to dose during the shift, and the hard stop that protects the day-sleep after it.

Day sleep is more fragile — use a stricter limit?

Last drink starts before

How it's computed

Same elimination model as the cutoff calculator (T½ 5 h base), but with a stricter bedtime limit: day sleep after a night shift is shorter and lighter, so we default to a 25 mg residual target instead of 50. Dose suggestions land caffeine at the circadian low point (~03:00–05:00) without poisoning the recovery sleep.

Caffeine Timeline · Cutoff calculator