Swimming calories burned depend on the stroke and how hard you push. An hour of steady freestyle burns about 365 kcal at 60 kg and 457 kcal at 75 kg; fast freestyle lifts that to around 617 to 772 kcal. Relaxed swimming that is not laps sits near the steady freestyle figure.
Water supports your weight, so swimming is gentle on joints while still working the whole body. That makes it a favourite for people with knee or back trouble.
Quick numbers
1 hour steady freestyle, 70 kg
about 426 kcal30 min breaststroke, 70 kg
about 195 kcal45 min leisure swim, 70 kg
about 331 kcal1 km freestyle, steady, 70 kg
about 213 kcal in about 30 minHardest stroke
butterfly, about 13.8 MET
Swimming calories burned per hour and per 30 minutes
| Stroke | MET | 30 min, 60 kg | 30 min, 75 kg | 1 hour, 60 kg | 1 hour, 75 kg |
|---|---|---|---|---|---|
| Leisure swimming, not laps | 6.0 | 189 | 236 | 378 | 472 |
| Freestyle, slow to moderate | 5.8 | 183 | 228 | 365 | 457 |
| Freestyle, fast | 9.8 | 309 | 386 | 617 | 772 |
| Breaststroke | 5.3 | 167 | 209 | 334 | 417 |
| Backstroke | 4.8 | 151 | 189 | 302 | 378 |
| Butterfly | 13.8 | 435 | 543 | 869 | 1,087 |
| Treading water, moderate | 3.5 | 110 | 138 | 220 | 276 |
Count swimming time, not pool time. Resting at the wall between lengths lowers the average.
1 km swimming calories burned
A recreational swimmer covers 1 km of freestyle in roughly 25 to 35 minutes. At 30 minutes and a steady effort, that is about 183 kcal at 60 kg and 228 kcal at 75 kg. A strong swimmer finishing in 20 minutes works harder per minute but for less time, so the total per km is similar or a little higher.
How the swimming calorie calculator works
kcal = MET × 3.5 × kg ÷ 200 × minutes
MET by stroke from the Compendium of Physical Activities
Choose the stroke you spend most of your time on, or split the session into parts and add them up.
Technique changes the number
Beginners often burn more per length than experienced swimmers because they fight the water. As technique improves, you move faster with less effort, so you need to swim further or harder for the same calories. Cold water adds a little, as the body works to stay warm.
Swimming for weight loss and fitness
Three 45 minute sessions a week burn roughly 1,000 to 1,400 kcal for most adults. Many swimmers feel very hungry after the pool, so plan a sensible snack rather than a large meal. Pair the pool with a food target from the deficit planner.
Learn to swim with a trained coach, swim where a lifeguard is present, and ask your doctor before starting if you have heart disease, epilepsy or uncontrolled asthma.
Compare with other low-impact cardio
Swimming sits close to brisk cycling for calories, and well above walking. For joint-friendly options see cycling and walking, or see all activities together on the calorie burn calculator.
Frequently asked questions
What does an hour of swimming burn?
About 365 to 457 kcal at a steady pace for 60 to 75 kg, and more with fast strokes.
How many calories does 30 min swimming burn?
About 167 to 386 kcal depending on stroke and weight.
How many calories are burned swimming 1 km?
Roughly 180 to 260 kcal for most adults at a steady freestyle.
Which swimming stroke burns the most calories?
Butterfly, followed by fast freestyle. Backstroke and breaststroke at an easy pace burn the least.
Is swimming good for losing weight?
Yes. It burns a useful amount and is easy on joints. Watch post-swim hunger.
How many calories does 45 min swimming burn?
About 274 to 343 kcal at a steady pace.
Sources
- Compendium of Physical Activities