Power Nap Timer
A free online nap timer. Pick 10, 20, 30, 60 or 90 minutes — or set your own — press Start, and it rings a clear alarm right in your browser when the nap is up.
Keep this tab open and your volume up — a browser timer can't ring once the tab closes or your phone locks. For a nap alarm that wakes you even over the lock screen, get AVA.
How long should a power nap be?
The single most important nap decision is length, because it determines which stage of sleep you wake up from. Nap too short and you barely rest; nap into deep sleep and wake mid-cycle, and you get sleep inertia — that heavy, disoriented fog that can leave you groggier than before you lay down. The trick is to either stay in light sleep or ride out a whole cycle.
| Nap length | What happens | Best for |
|---|---|---|
| 10–20 min The power nap | You stay in light (stage 1–2) sleep and wake before deep sleep starts. Quick alertness and mood lift, essentially no grogginess. | A mid-afternoon reset, a pick-me-up before driving or a meeting. |
| 30 min | Borderline. You may just dip into deep sleep, so you can wake up briefly groggy before the benefits kick in a few minutes later. | People who find 20 minutes too short but can tolerate a short wake-up fog. |
| 45–60 min | Usually the worst nap. The alarm tends to land in slow-wave deep sleep, producing the strongest sleep inertia. It can help learning and memory once you shake it off. | Fact and memory consolidation — if you can afford to feel rough on waking. |
| 90 min The full cycle | One complete sleep cycle through deep sleep and REM, ending back in light sleep — so you wake more naturally and refreshed, with a boost to creativity and memory. | When you're genuinely sleep-deprived and have the time for a real recovery nap. |
For most people, on most days, 10–20 minutes is the sweet spot. It delivers the alertness payoff without the risk of waking from deep sleep. Reach for 90 minutes only when you're truly short on sleep and can spare the time; the 45–60 minute range is the one to avoid unless memory work is the whole point.
Is a 20-minute nap enough?
Yes — for daytime alertness, 20 minutes is plenty. Because you wake before slow-wave deep sleep, you get most of the restorative "reset" of a nap with almost none of the grogginess. NASA's often-cited research on pilots found even short naps sharply improved alertness and performance. Set the timer for 20 minutes and count the few minutes it takes to actually drift off as a bonus wind-down rather than lost time.
Why do I feel worse after a long nap?
That heavy, hungover feeling is sleep inertia, and it comes from waking during deep (slow-wave) sleep instead of light sleep. About 30 minutes in, you start descending into deep sleep; an alarm at the 45–60 minute mark tends to yank you out of the deepest stage, which is exactly when your brain is least ready to switch on. The fix is to keep the nap short enough to stay out of deep sleep (under ~25 minutes) or long enough to climb back out of it (a full 90-minute cycle). If you regularly need long, groggy naps to get through the day, that's often a sign of a nighttime sleep debt — see how much sleep you actually need.
The best time to nap
Aim for early-to-mid afternoon, roughly 1:00–3:00 PM. That's when most people hit the natural post-lunch dip in their circadian rhythm, so you'll fall asleep faster and the nap won't cut into your night. Napping too late — after about 4:00 PM — bleeds off the "sleep pressure" you need to fall asleep at bedtime and can push your whole night later. If you want to nap and still protect a specific wake-up time, plan the night with a sleep calculator so the nap doesn't steal from your core sleep.
The coffee nap trick
If you want the strongest possible short-nap boost, try a coffee nap: drink a cup of coffee, then immediately lie down for a 20-minute nap. Caffeine takes about 20 minutes to reach your brain, so you wake up just as it kicks in — and because the nap clears out adenosine (the molecule that makes you feel sleepy, and the one caffeine blocks), the two effects stack. Set this timer to 20 minutes, down the coffee, and start it in the same breath.
Naps patch the day. AVA fixes the mornings.
AVA is an AI alarm clock and habit companion. Instead of the same tone your brain has learned to sleep through, it speaks a brand-new, personalized wake-up message every morning — tied to your goals and your streak, over wake-up music — so waking up never goes stale. It also tracks wake-up streaks, quit-alcohol and quit-nicotine recovery milestones, and fitness goals.
Get AVA on Google Play — FreeAndroid today; iPhone version launching — follow it here. Free tier includes 7 AI-voice wake-ups a month, then falls back to a standard tone. Premium is $9.99/month. AVA is a newer app and not a sleep tracker.
FAQ
- How long should a power nap be?
- For most people, 10–20 minutes. That keeps you in light sleep so you wake up alert instead of groggy. If you're badly sleep-deprived and have the time, a full 90-minute cycle is the other good option; the 45–60 minute range tends to leave you the most foggy.
- Is a 20-minute nap enough?
- Yes. A 20-minute nap gives you most of a nap's alertness and mood benefit while avoiding deep sleep, so you wake up clear-headed. It's the go-to "power nap" length. Allow a few extra minutes to actually fall asleep.
- Why do I feel worse after a long nap?
- Because you woke up out of deep sleep. That's called sleep inertia — a groggy, disoriented state that hits hardest when an alarm interrupts slow-wave sleep around the 45–60 minute mark. Keep naps under about 25 minutes, or go a full 90-minute cycle, to wake from lighter sleep instead.
- What's the best time of day to nap?
- Early-to-mid afternoon, about 1:00–3:00 PM, when your circadian rhythm naturally dips. Napping much later than 4:00 PM can make it harder to fall asleep at night.