Sleep Efficiency Calculator

Sleep efficiency is one of the most widely used metrics in sleep research and in cognitive behavioral therapy for insomnia (CBT-I): it relates how much time you spend in bed to how much of that time is actually sleep, not wakefulness.

It does not measure sleep quality in an absolute sense (stages, depth, overnight heart rate): it only measures the proportion of time in bed that translates into actual sleep. Low efficiency can indicate difficulty falling asleep, frequent night-time awakenings, or simply time spent awake in bed before getting up.

Full guide: sleep efficiency formula, worked example and interpretation →

Simple mode is enough if you already know two numbers: how long you were in bed in total, and how much of that time you slept (for example from a sleep app or a personal estimate). It's the most direct calculation, no precise clock times needed.

Advanced mode breaks the night down: the time you went to bed/turned the lights off, the time you got up, how long it took you to fall asleep (latency), how long you were awake during the night, and how long you stayed awake in bed after your final wake-up before getting up. From these values, sleep time is derived, not entered directly - useful if you want to see where the non-sleep time in bed actually goes.

In advanced mode you only enter clock times (e.g. 11:30 PM, 7:15 AM), never real calendar dates: if the out-of-bed time is earlier than the bedtime, the calculator automatically assumes it's the next day. Since no real calendar date is ever used, there are no daylight-saving-time (DST) implications to handle.

Operational definition used: Time in Bed (TIB) = from bedtime to out-of-bed time. Total Sleep Time (TST) = TIB minus sleep onset latency, minus time awake during the night, minus time awake after the final wake-up. Sleep Efficiency = TST / TIB × 100.

This is not the only operational definition in the literature: the "time in bed" denominator is the subject of an explicit methodological debate (see Sources, Reed & Sacco 2016), because different studies/devices calculate it in slightly different ways. This tool states its own definition explicitly, instead of presenting a single number without explaining where it comes from.

In bed at 11:30 PM, final wake-up at 7:15 AM: time in bed = 7 hours 45 minutes (465 minutes). It took 15 minutes to fall asleep, you were awake 20 minutes during the night, and stayed awake in bed 5 minutes after your final wake-up before getting up: total awake time = 40 minutes.

Sleep time = 465 − 40 = 425 minutes (7 hours 5 minutes). Sleep efficiency = 425 / 465 × 100 ≈ 91.4%.

This tool does not diagnose anything and does not replace a clinical sleep assessment (polysomnography, professional actigraphy, or a consultation with a sleep physician). It does not show "good/bad" rating bands: it only shows the number calculated from the data you enter.

The values you enter (especially in simple mode) are often personal estimates, not objective measurements: subjective perception of how much you slept is known to be imprecise, especially for sleep onset latency and brief awakenings you don't remember in the morning.

The "time in bed" denominator does not have a single definition in the literature (see the previous section and Reed & Sacco 2016 in Sources): comparing the efficiency calculated here with that of another tool/device using a different definition can give different numbers for the same night.

All calculation happens in your browser: the times and durations you enter are never sent to a server, are not saved by FitMesh, and never appear in the page URL. Closing or reloading the page clears whatever you entered.

CSV export and copying the summary happen locally on your device (direct download or clipboard), with no external service involved.