Sleep Efficiency Calculator
Work out the percentage of your time in bed that you spent asleep from bed and wake times, or from minutes in bed and asleep.
Result
Fill in the fields above, then press Calculate.
The sleep efficiency calculator shows what share of your time in bed you actually spent asleep. Enter a bed and out-of-bed time, plus the minutes you took to fall asleep and spent awake in the night, or enter minutes in bed and minutes asleep directly. The result is informational, not a diagnosis.
Examples
In bed 11:00 PM to 7:00 AM, 20 minutes to fall asleep, 30 minutes awake
Time in bed = 8 h 00 min (480 minutes). Time asleep = 480 - 20 - 30 = 430 minutes. Efficiency = 430 / 480 x 100 = 89.6%. At or above 85%, the level the National Sleep Foundation expert panel treated as good sleep quality.
7 hours in bed, 5 hours 30 minutes asleep
330 / 420 x 100 = 78.6%. Above 74% but below 85%, under the good-quality level but above the level the panel flagged as low. For adults aged 18 to 25 the panel's lower cut-off is 64%. One night proves little; look at several nights.
9 hours in bed, 8 hours 30 minutes asleep
510 / 540 x 100 = 94.4%. A high efficiency says nothing about whether 8.5 hours is the right amount of sleep for you; it only measures how much of your time in bed was spent asleep.
Sleep efficiency for 8 hours in bed
| Time asleep | Time awake in bed | Sleep efficiency |
|---|---|---|
| 7 h 30 min | 30 min | 93.8% |
| 7 h 00 min | 1 h 00 min | 87.5% |
| 6 h 30 min | 1 h 30 min | 81.3% |
| 6 h 00 min | 2 h 00 min | 75% |
Frequently Asked Questions
What is sleep efficiency?
Sleep efficiency is the ratio of time asleep to time in bed, shown as a percentage. If you spend 8 hours in bed and sleep 7, your efficiency is 87.5%.
What is a good sleep efficiency?
A National Sleep Foundation expert panel judged a sleep efficiency of 85% or higher to indicate good sleep quality, and 74% or lower not to (Ohayon et al., 2017); for young adults aged 18 to 25 the lower figure was 64%. Figures in between are neither. These are population guides, not a personal diagnosis.
Is 100% sleep efficiency good?
Not necessarily. Efficiency only compares sleep with time in bed. It is not a measure of how much sleep you got or how rested you feel. Look at total sleep time as well.
Does time in bed include the time before I fall asleep?
Yes. Time in bed runs from getting into bed to getting out, so the minutes you lie awake before falling asleep, the minutes you are awake in the night, and any time you lie awake before getting up all lower your efficiency.
Should I worry about a low result?
A low figure on one night is common and not a reason to worry. If your efficiency stays low across many nights, or you feel tired during the day, speak to a clinician. This calculator gives information only and cannot diagnose a sleep problem.
How accurate are the minutes from my sleep tracker?
Consumer trackers estimate sleep rather than measure it directly, so their minutes asleep and awake are approximate. A short sleep diary is an alternative. Either way, treat the result as a rough guide.
Related Information
Related sleep tools
- Sleep calculators and guides - every sleep calculator and bedtime guide in one place.
- Sleep Cycle Calculator - Bedtimes and wake-up times from 90-minute sleep cycles.
- Sleep Debt Calculator - How many hours short of your target the last week left you.
- Nap Calculator - When to set the alarm for a 20-minute or 90-minute nap.
Key Terms
- Sleep efficiency
- Time asleep divided by time in bed, as a percentage.
- Sleep latency
- The minutes it takes to fall asleep after getting into bed.
- Wake after sleep onset
- Minutes spent awake after first falling asleep.
Sources
- Ohayon et al., National Sleep Foundation's sleep quality recommendations: first report — Sleep Health, 2017;3(1):6-19
- CDC: About Sleep — U.S. Centers for Disease Control and Prevention
Result
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Quick Tips
- •Average several nights before drawing conclusions; a single night is noisy.
- •Spending less time in bed awake raises efficiency, but do not cut your time in bed sharply without advice, since you may end up sleeping too little.
- •Going to bed and getting up at the same time every day is one of the habits the CDC lists for better sleep.
- •Use the sleep cycle calculator to pick a bedtime for your wake-up time.