Choose a nap length tuned to sleep-cycle research, see your estimated wake-up time, and start a countdown with an alarm so you don't oversleep.
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Pick a preset nap length or enter a custom one, adjust how long you typically take to fall asleep, and check your estimated wake-up time. Select Start nap timer to begin a countdown that includes your fall-asleep buffer, with an alarm when it's time to wake up.
Sleep moves through cycles of light sleep, deep sleep and REM sleep, each lasting roughly 90 minutes. A short 10–20 minute nap keeps you in light sleep, so you wake up refreshed rather than groggy. A 26-minute nap was famously used by NASA in studies on pilot alertness. Longer naps that stretch to around 90 minutes let you complete a full cycle, avoiding the grogginess of waking mid-deep-sleep, though at the cost of a longer time commitment.
Naps in this range often wake you during deep sleep, which is the most common cause of post-nap grogginess (sleep inertia).
Early-to-mid afternoon naps are generally easier to fall asleep for and less likely to disrupt nighttime sleep than naps later in the day.
Common questions, answered.
The countdown covers the total time from lying down to waking up, not just the nap itself, so it adds your estimated time to fall asleep to the nap length before starting the alarm countdown.
It refers to a NASA study that found a roughly 26-minute nap significantly improved pilot performance and alertness without leaving them groggy, making it a popular power nap benchmark.
Naps in that range often end while you're in deep sleep, and waking from deep sleep causes sleep inertia — grogginess and reduced alertness that can last 15–30 minutes afterward.
Yes, if you have the time. A 90-minute nap approximates one full sleep cycle, letting most people wake near a natural light-sleep point, though it's a bigger time commitment than a short power nap.