Swimming calories calculator

Pick your stroke and pace and see the energy for your session.

Your details

Activity

Minutes

min

Your weight

stlb

Sessions a week (optional)

Sex (optional, to personalise)

Age (optional)

years

Height (optional)

Another activity (optional)

Minutes of it

min

And another (optional)

Minutes of that

min

Pool length (optional)

Lengths swum (optional)

lengths

30 min of front crawl, slow

181 kcal

extra over resting, for your weight; add age, sex and height to personalise

Total, including what you burn at rest213 kcal
Your resting burn over that time32 kcal (1,529 kcal a day)
Effort for you (corrected METs)6.7 METs, against 5.8 for the standard 3.5 ml/kg/min
Personalised withaverage adult figures (add age, sex and height)
Effort level5.8 METs, moderate
Each week (2 sessions)362 kcal on top of resting
Counts towards your 150 weekly minutes60 minutes
Distanceadd your pool length and lengths swum to see the distance and your average pace

The headline is the extra energy the activity used on top of what you would burn resting, which is the part that counts against food. Figures use the 2024 Compendium corrected METs and can be 20% out either way; fitness, technique and how hard you go all move them.

The working

30 minutes of easy front crawl

Slow front crawl is 5.8 METs. The standard sum is METs × 3.5 × kg ÷ 200 per minute, so at 11 st (69.9 kg) 30 minutes uses 213 kcal in total. About 32 kcal of that you would have burned resting anyway (Harris-Benedict for an average 40 year old, 170 cm), leaving 181 kcal extra. Two swims a week give 60 moderate minutes.

Add your sex, age and height to personalise it. The 2024 Compendium corrects each MET for your own resting rate, so the extra kcal shifts a little: a shorter, older woman burns less at rest, so more of the total counts as extra.

A mixed session

Up to three strokes

Most swims mix strokes. Add the others with their minutes and we add them up stroke by stroke, with the moderate and vigorous minutes towards your 150 a week. Add the pool length and lengths swum to see the distance: 40 lengths of a 25 m pool in 50 minutes is 1,000 m, about 5:00 per 100 m with the rests at the wall included.

Strokes compared

Recreational and training

Stroke	Relaxed	Training
Front crawl	5.8	9.8
Breaststroke	5.3	10.3
Backstroke	4.8	9.5
Butterfly		13.8

Getting better

Small changes

A few lessons improve technique fast
Use a kickboard for leg only lengths
Breathe every 3 strokes in crawl
Swim England runs adult lessons

Read with care

What this cannot tell you

Stops at the wallLong rests lower the average.
TechniqueEfficient swimmers use less energy at the same speed.
Open waterCold and waves change everything; never swim alone.

Questions

Common questions

How many calories does swimming burn?

About 200 to 400 kcal in 30 minutes for an 11 stone adult, depending on pace.

Which stroke burns the most calories?

Butterfly, then fast breaststroke and crawl.

Is swimming good for bad knees?

Usually, though breaststroke kick can bother some knees.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

Before you push on

New to exercise, or got a heart, lung or joint condition? Have a word with your GP or practice nurse first. Stop and get help if you feel chest pain, faintness or unusual breathlessness, and call 999 if it is severe.