You burn calories even while you sleep, and for most people it’s a surprisingly meaningful amount.

Quick Scoop

  • Average burn: about 50–70 calories per hour of sleep.
  • For 8 hours in bed, that’s roughly 400–500 calories overnight for many adults.
  • This is only about 15% less than what you burn when you’re awake but resting quietly.
  • The exact number depends on your weight, age, muscle mass, health, and how long you sleep.
  • Most of the calorie burn comes from your basal metabolic rate (keeping your heart, brain, and organs running) plus brain activity during deeper and REM sleep.

A simple example

If your daily basal metabolic rate is around 1,600 calories, you’d burn about 66 calories per hour at rest; over 8 hours of sleep, that could be a bit over 500 calories.

So while sleep isn’t a “fat‑burning hack” on its own, a full night of good‑quality sleep quietly uses a few hundred calories in the background every single night.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.