Your body never truly powers down — even in deep sleep, your heart beats, your lungs move, and your brain runs maintenance. That background burn adds up to several hundred calories every night. Want your own number? Our BMR calculator finds your personal daily burn rate in seconds, and the walkthrough below shows you exactly how to turn that into a per-hour and per-night sleep estimate.
Most adults burn roughly 50 to 110 calories per hour while sleeping, depending mainly on body weight. A 150 lb (68 kg) adult burns about 68 calories per hour — around 544 calories across 8 hours. A heavier sleeper burns more: a 210 lb (95 kg) adult burns about 95 calories an hour, or roughly 762 across the night. Sleep itself is close to your basal metabolic rate (BMR), your body's idling engine — so if you know your BMR, you can estimate your sleep burn in two steps.
Using the standard rule of thumb — BMR of about 24 calories per kilogram of body weight per day, or roughly 1 calorie per kg per hour:
| Body weight | Calories per hour (approx.) | Calories per 8-hour night (approx.) |
|---|---|---|
| 120 lb (54 kg) | 54 | 435 |
| 150 lb (68 kg) | 68 | 544 |
| 180 lb (82 kg) | 82 | 653 |
| 210 lb (95 kg) | 95 | 762 |
| 240 lb (109 kg) | 109 | 871 |
These figures assume your hourly burn equals your BMR rate. In reality, sleeping metabolic rate runs about 5–10% below waking BMR — your body is genuinely thrifty at night — so treat the chart as a slightly high-side estimate.
Researchers most commonly estimate BMR with the Mifflin-St Jeor equation. Once you have BMR, divide by 24 for an hourly rate, then multiply by hours slept. Here is the full worked example.
Example: 30-year-old man, 5 ft 10 in (178 cm), 180 lb (82 kg).
His average hourly burn: 1,783 ÷ 24 = 74.3 calories per hour. Over 8 hours of sleep: 74.3 × 8 = 594 calories per night — before the small sleeping discount (subtract 5–10% for a truer figure, roughly 535 to 565).
Example: 28-year-old woman, 5 ft 4 in (163 cm), 150 lb (68 kg).
Prefer to skip the math? The step-by-step version with a shortcut sits in our guide to calculating BMR by hand, and your total daily burn — sleep plus everything else — is what our TDEE calculator solves for.
Here is the counterintuitive part: the calories you burn during sleep are not the interesting story. The interesting story is what too little sleep does to the rest of your day.
Two hormones help regulate hunger: ghrelin (which signals hunger) and leptin (which signals fullness). Research has repeatedly found that short sleep is associated with higher ghrelin and lower leptin — a hormonal combo that nudges you toward eating more the next day, especially sugary, calorie-dense foods. That is one reason a 6-hour night followed by a bagel, a muffin, and an extra coffee with cream can quietly erase a day's careful eating.
Studies also suggest poor sleep reduces self-control around food and increases time spent awake (and snacking). The takeaway: protecting 7–9 hours of sleep may help your weight goals more than worrying about the 500-odd calories burned during the night itself. Our sleep calculator can help you pick a bedtime that fits your wake-up time.
You burn several hundred calories every night — roughly 400 to 870 across 8 hours depending on your size — but you cannot "sleep off" weight. Sleep's real contribution to fat loss is hormonal: consistent, sufficient sleep helps keep ghrelin and leptin (and your appetite) in check, making your daytime diet far easier to stick to.
Disclaimer: This content is for informational purposes only and is not medical advice. Calorie estimates here are approximations — individual metabolism varies with muscle mass, age, hormones, and health conditions. If you have a sleep disorder, a medical condition, or take medication that affects sleep or metabolism, talk to your doctor before changing your routine.
Written by the Live Fitness Check editorial team · Reviewed against our calculator methodology · Last updated October 2026
