By Zencalcy Editorial TeamLast reviewed About us
Get an honest estimate of the calories you burn while sitting in a sauna. Heat exposure raises your heart rate and energy use a little, but the effect is modest, so this should not be treated as exercise.
Get a modest estimate of calories burned in a sauna.
kcal ≈ 1.8 × weight (kg) × time (hours)
A typical sauna session sits near 1.5 to 2 MET, so this uses about 1.8. Much of any weight lost in a sauna is water, not fat, and it returns when you rehydrate.
| Symbol | Meaning |
|---|---|
| weight | Your body mass in kilograms. |
| minutes | How long you sat in the sauna, in minutes. |
| temperature | Optional sauna temperature in degrees Celsius, for your notes. |
An 80 kg person spending 20 minutes in the sauna burns roughly 1.8 × 80 × 0.333 ≈ 48 kcal. That is far less than the same time spent walking, so the sauna is not a workout.
Sitting in a sauna raises your heart rate and skin temperature and makes you sweat, but it is not exercise, and the body is not performing the mechanical work that drives most calorie burn. Any increase in metabolic rate from passive heating is small, far below the cost of even a slow walk.
The weight you appear to lose after a sauna is almost entirely water, which is replaced as soon as you drink. It is not fat loss, and reading the scale drop as burned calories is a common but mistaken interpretation.
Some devices and articles quote a large calorie figure for sauna time, but these numbers are typically modeled from heart rate, which rises in heat without a matching rise in oxygen consumption. Heart rate based calorie tools therefore overestimate badly in a hot room.
The honest position is that a sauna session burns a modest amount above resting, on the order of a short easy activity, and contributes little to weight management on its own. Its real benefits are relaxation and heat acclimation, not calorie expenditure.
Continue with the Snow Shoveling Calories Calculator, Stairs Calorie Calculator, or the Steps to Calories Calculator — or browse more calories burned tools and all sports calculators.
Only in the sense that you lose water weight, which comes back as soon as you drink. It does not burn meaningful fat.
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Content updated: September 2026