Power Nap vs Full Cycle Calculator

How it is calculated

You enter the minutes you have before you must be up and the minutes you usually need to fall asleep. The tool first works out the time you can actually sleep: sleep = available − fall_asleep. Then it picks a nap by fixed thresholds. If sleep ≥ 90 it recommends one full 90-minute cycle, however much longer the window is. If sleep is from 20 up to just under 90 it recommends a 20-minute power nap. Below 20 it says only a very short nap fits and proposes the whole sleep time. The tool gives no result if the available time is zero or over 240 minutes, if the fall-asleep time is negative or over 60, or if nothing is left after falling asleep. It does not add a buffer for waking up, and the 90-minute cycle length is a fixed average.

Common mistakes

• Entering the whole break as available time but forgetting that falling asleep eats into it. A 25-minute break with 10 minutes to fall asleep leaves only 15 minutes of sleep, and the tool says only a very short nap fits.
• Entering a fall-asleep time of zero as a habit. If it really takes you 15 minutes, the result changes: 105 minutes available only just allows the full cycle, while 104 drops you to the 20-minute nap.
• Filling the whole available time with sleep. With 60 minutes, the tool recommends 20 minutes, not 50, because the longer nap would end in the deeper part of a cycle.
• Setting the alarm for the available time instead of the nap length. The best nap figure is how long to sleep, and the alarm should be counted from when you fall asleep.
• Entering the time in hours. The fields are in minutes, so one and a half hours is 90; a fall-asleep time over 60 or an available time over 240 gives no result.