Wake up from your nap refreshed

Nap calculator: how long should you nap?

A nap can rescue an afternoon or ruin a night, and the difference is mostly timing and length. This nap calculator takes the time you plan to lie down, adds a few minutes to fall asleep, and shows the wake-up times for the standard nap lengths: a 20-minute power nap, a 30-minute nap, a 60-minute nap and a full 90-minute cycle. You can see at a glance which option fits the time you actually have.

People who search for "how long should I nap", "best nap length" or "nap time calculator" are usually trying to avoid one thing: waking up groggy. The short answer is to stay under about 30 minutes or sleep a full 90 minutes. The stretch in between is where deep sleep starts and where waking up feels worst.

What each nap length does

10 to 20 minutes keeps you in light sleep. It usually improves alertness and mood without leaving you foggy, which is why it is called a power nap. 30 minutes can start to reach deeper sleep, so you may feel groggy for a short while, though many people still benefit. 60 minutes contains plenty of deep sleep and can help memory, but waking in the middle of it is the classic recipe for sleep inertia. 90 minutes is a full sleep cycle, so you can wake naturally in lighter sleep, but it is long enough to affect your sleep that night if taken late.

How to use the calculator

Choose the time you will lie down. The tool adds around 10 to 15 minutes to fall asleep, since few people drop off the instant they close their eyes, and then displays the alarm times. Set your phone to the time that suits you and keep the room dim and quiet. If you do not fall asleep at all, the rest still helps, so do not treat it as a failure. For a countdown that also plays a gentle chime, try the power nap planner.

The best time of day for a nap

Most people have a natural dip in alertness in the early afternoon, roughly seven to eight hours after waking. A nap between about 1 PM and 3 PM fits that dip and is unlikely to disturb night sleep. Naps after about 4 PM can push your bedtime later, especially if they are long. If you are a night-shift worker the same logic applies, only relative to your own day. See the shift work sleep planner for how to place naps before and during a run of nights.

Napping and caffeine: the coffee nap

A coffee nap means drinking a coffee and sleeping for 15 to 20 minutes straight away. Caffeine takes about 20 to 30 minutes to start working, so you wake up as it arrives. Several small studies suggest this can reduce drowsiness more than either approach alone. It only works as an occasional trick, and not late in the day. Use the caffeine cutoff calculator to check that your last coffee does not collide with bedtime.

Who should be careful with naps

If you struggle to fall asleep at night, or you have insomnia, regular naps can reduce the pressure to sleep at bedtime, and some sleep clinicians suggest avoiding them. If you feel the need to nap every day despite sleeping a full night, mention it to a doctor. Persistent daytime sleepiness can be a sign of a sleep disorder such as sleep apnea. Babies and toddlers follow different rules, so use the baby wake window tool and the baby nap schedule for them.

Naps and sleep trackers

Many wearables log naps automatically, though they can miss short ones, and some require you to start a workout-style session. If you want to know whether your naps change your night, compare weeks with and without them in a sleep diary or in the app of your watch or ring. Our best sleep tracker guide explains which devices handle naps well and what to ignore in the data.

Nap lengths at a glance

If you lie down at 2:00 PM and take 10 minutes to fall asleep, a 20-minute nap ends at 2:30 PM, a 30-minute nap at 2:40 PM, a 60-minute nap at 3:10 PM and a full 90-minute cycle at 3:40 PM. The calculator does this sum for any start time. Setting an alarm for the end of the nap, not the start, is the most common mistake: it makes your nap shorter than you meant.

How naps relate to your night sleep

Napping borrows sleep pressure from the night. If you nap for an hour in the afternoon you may find it harder to fall asleep at your usual bedtime. When your night sleep is good, a short nap is a bonus. When your night sleep is poor, consistent naps can become a crutch, and the better solution is to fix the nights using the bedtime calculator and a steady wake-up time.

Napping at work or school

Where napping is possible, a dark, quiet corner, a timer and a 15 to 20 minute limit are enough. Many workplaces now offer nap rooms because short naps are linked to better alertness and fewer errors. If you cannot lie down, a reclined chair or even resting your head on a desk with your eyes closed gives some benefit. Remember to set the alarm.

Frequently asked questions