How to use
- Press Now, or enter the time you plan to lie down.
- Set how long you usually take to fall asleep.
- Set your alarm for one of the two times, a power nap or a full cycle.
Options explained
- Power nap
- 10–20 minutes of light sleep. You wake up alert, which suits a short lunch break.
- Sleep inertia
- The groggy, slow feeling after waking from deep sleep, usually lasting 15–30 minutes. Naps of 40 minutes to an hour are the most likely to cause it.
Nap length and how you wake up
| Length | How you’ll feel | Good for |
|---|---|---|
| 10–20 minutes | Alert, ready to carry on | Lunch breaks, drowsy driving |
| 30–60 minutes | Groggy, maybe a headache for a while | Best avoided |
| About 90 minutes | One full cycle, much more rested | Weekends, after a bad night |
These lengths are time asleep; the calculator adds the time you take to fall asleep.
Drowsy at the wheel
Pull into the next rest area and take a 15–20 minute nap, then walk around before setting off again. Opening the window or turning up the radio only helps for a few minutes.
To plan a whole night, use the sleep calculator; to see how much sleep you’ve missed this week, use the sleep debt calculator.
Frequently asked questions
Why do I feel worse after a 45-minute nap?
About 30 minutes after you fall asleep you reach deep sleep. An alarm then leaves you with sleep inertia, a foggy head and low energy. Get up within 20 minutes, or sleep a whole cycle.
When is the best time to nap?
After lunch and before 3 pm. Most people have a natural dip in alertness in the early afternoon, so it is easy to fall asleep; a long nap later in the day makes it harder to sleep at night.
Is it worth lying down if I can't fall asleep?
Yes. Resting quietly with your eyes closed for 15–20 minutes still helps with tiredness. Try not to keep checking the time.
Does a coffee nap work?
Caffeine takes about 20 minutes to kick in, so drinking a coffee and then napping for 15–20 minutes means it starts working as you wake. A 1997 study by Reyner and Horne found this helped sleepy drivers more than coffee or a nap alone. Skip it if you sleep badly at night.
Privacy
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