Sleep Midpoint Calculator

About this calculator

Your sleep midpoint is the exact halfway point between bedtime and wake time — a core measure in chronobiology because, unlike total sleep duration, it captures when in the 24-hour cycle you sleep, which is what defines your chronotype (how much of an early bird or night owl you are).

Researchers compare a person's midpoint on workdays versus free days to quantify social jet lag — the mismatch between the body's internal clock and a socially imposed schedule, which has been linked to daytime fatigue and metabolic strain. This calculator is used by sleep researchers, people tracking their circadian rhythm, and anyone checking whether their daily schedule actually fits their natural sleep pattern.