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Napping is a skill with a trapdoor: done right it restores alertness, memory and mood; done wrong it leaves you groggier than before — and if timed too late, it steals from the night ahead. The science is clean: short naps end before deep sleep, long naps complete a full cycle, and the 45-60 minute middle ground is where naps go wrong. This calculator tells you which zone your nap falls in.
Naps are a science: 20 minutes refreshes, 90 minutes completes a cycle — and the 45-60 minute range is where naps go wrong.
At 45-60 minutes you wake from deep sleep — sleep inertia. End naps at 20 minutes or commit to the full 90-minute cycle.
Early afternoon (roughly 1-3pm) fits the natural dip in alertness; napping later reduces your sleep pressure for the night.
Yes — a power nap improves alertness and performance for hours without leaving you groggy or disrupting nighttime sleep.
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