Choose when you’ll lie down and see when to wake up for a quick nap, a power nap or a full sleep cycle.
| Nap | Length | What to expect |
|---|---|---|
| Quick nap | 10 minutes | In a study of sleep-restricted adults, a 10-minute nap improved alertness straight away, with almost no grogginess, and the benefit lasted about 2.5 hours. |
| Power nap | 20 minutes | Similar benefits, but you may feel slightly groggy for a few minutes afterwards. |
| Avoid | 30 to 60 minutes | Long enough to reach deep sleep, so you are more likely to wake up groggy (sleep inertia), which can last 30 minutes or more. |
| Full cycle | 90 minutes | One complete cycle with light, deep and REM sleep. You wake from lighter sleep. Useful if you are very short on sleep or before a night shift, but it can make it harder to sleep at night. |
The times in the calculator include the time it takes you to fall asleep, so set the alarm for the time shown, not 20 minutes from when you lie down.
For most people who sleep at night, the best time is early afternoon, about 6 to 8 hours after waking up, which is around 1 PM to 3 PM. That is when the body clock causes a natural dip in alertness. Napping later than about 4 PM, or within 6 to 7 hours of bedtime, can make it harder to fall asleep at night.
If you work nights, a nap before your shift can help you stay alert. Use our shift work planner to time it.
Caffeine takes around 20 to 30 minutes to kick in, so some people drink a coffee just before a 20-minute nap and wake up as it starts to work. It’s a popular trick, but keep it to earlier in the day: caffeine can still disturb your sleep 6 hours later. Check with our caffeine cut-off calculator.
For general information only, not medical advice. If you often feel tired despite enough sleep, snore loudly, or have trouble sleeping most nights, talk to a doctor.