How many calories does swimming burn?
Swimming is expensive, but less than what you read everywhere — for a reason that has nothing to do with effort.
The maths runs in your browser: your weight is not sent anywhere.
Hourly expenditure
| Weight | Easy · 5.3 MET | Moderate · 7 MET | Hard · 9.8 MET |
|---|---|---|---|
| 60 kg | 271 kcal | 378 kcal | 554 kcal |
| 70 kg | 316 kcal | 441 kcal | 647 kcal |
| 80 kg | 361 kcal | 504 kcal | 739 kcal |
| 90 kg | 406 kcal | 567 kcal | 832 kcal |
Estimated additional burn
What moves the number
Published swimming figures describe CONTINUOUS swimming. A real session contains stops at the wall, instructions, recoveries: counting the total time at the pool overstates it heavily. Count the time actually spent swimming. Technique also matters more than elsewhere — an efficient swimmer burns LESS for the same distance.
Why this number is lower than elsewhere
The MET formula gives TOTAL expenditure during effort, rest included — an hour sitting down is already 1 MET. Most calculators display that gross figure. The problem: your basal metabolism is already counted in your daily calorie needs. Showing the gross number counts it twice.
We subtract the resting MET and report only what the effort cost ON TOP. Thirty minutes of walking gives roughly 100 kcal here, against 140 elsewhere. It is less flattering, and it is the only number that does not contradict itself when you step on the scale a month later.
It is also why these calories are never handed back to your food budget in the app: a workout is not a licence to eat.
Where the number comes from
A MET measures the cost of an activity relative to rest: 8 MET is eight times what a still body burns. The values used here come from the Compendium of Physical Activities (Ainsworth et al., 2011), the reference table of physical activity research.
Expenditure is then: (MET − 1) × 3.5 × weight in kg × minutes ÷ 200. Weight matters because you have to move it; duration matters more than anything else.
These are population estimates. Two people of the same weight doing the same effort can differ by 10 to 15 %: fitness, technique, temperature. Use these numbers to compare sessions with each other, not to balance a day to the calorie.
See also
Running
Minute for minute, running is the most expensive of the sixteen. Here is what it actually costs at your weight and pace.
Cycling
Cycling has the widest gap between “a ride” and “an effort” of any activity here: triple, end to end.
Walking
Walking is the most underrated activity here: cheap by the minute, but the one you do for the longest.
General, informational benchmarks based on published values validated on the general population. Real expenditure varies between two people with the same profile. These numbers do not replace a doctor or dietitian.