Swimming Calorie Calculator: kcal by Stroke, Time & Distance

A 70 kg swimmer doing steady front crawl burns about 280 kcal in 30 minutes and 560 kcal in an hour, or roughly 200 kcal per kilometre (8.0 METs, 2024 Adult Compendium). Gentle swimming or easy breaststroke comes to about 370 to 420 kcal an hour. The swimming calorie calculator below works out your figure by time or distance.

Enter the minutes you were actually swimming, not the time from changing room to changing room. A 60-minute session with 15 minutes resting at the wall is 45 minutes of swimming: about 420 kcal of steady crawl at 70 kg, not 560.

How many calories does swimming burn by stroke?

For a 70 kg swimmer, an hour ranges from about 335 kcal of easy backstroke to about 965 kcal of butterfly. Here is each stroke and effort the calculator offers, per hour, with its MET value:

• Butterfly: about 965 kcal (13.8 METs)
• Front crawl, fast, about 1:27 per 100 m: about 735 kcal (10.5 METs)
• Breaststroke, hard: about 720 kcal (10.3 METs)
• Front crawl, moderate, about 2:10 per 100 m: about 560 kcal (8.0 METs)
• Gentle swimming, not lengths: about 420 kcal (6.0 METs)
• Front crawl, easy, about 2:56 per 100 m: about 405 kcal (5.8 METs)
• Breaststroke, recreational: about 370 kcal (5.3 METs)
• Backstroke, easy: about 335 kcal (4.8 METs)

Breaststroke has the widest spread of any stroke: swum hard it costs nearly twice as much as a relaxed recreational breaststroke. Butterfly tops the list, though almost nobody holds it for an hour. Calories scale directly with body weight, so an 85 kg swimmer adds about a fifth to every figure and a 60 kg swimmer takes about a seventh off.

How many calories do 20, 30 and 45 minutes of swimming burn?

Twenty minutes of moderate front crawl burns about 185 kcal for a 70 kg swimmer, 30 minutes about 280 and 45 minutes about 420. The same sessions at other efforts:

• 20 minutes: about 125 kcal recreational breaststroke, 140 gentle swimming, 185 moderate crawl, 245 fast crawl
• 30 minutes: about 185 kcal recreational breaststroke, 210 gentle, 280 moderate crawl, 370 fast crawl
• 45 minutes: about 280 kcal recreational breaststroke, 315 gentle, 420 moderate crawl, 550 fast crawl
• 1 hour: about 370 kcal recreational breaststroke, 420 gentle, 560 moderate crawl, 735 fast crawl

How many calories does swimming 1 km burn?

Swimming 1 km of front crawl burns about 200 kcal for a 70 kg swimmer at a moderate pace, which takes about 22 minutes. For the distances people swim most, with lengths of a 25 m pool:

• 250 m (10 lengths): about 50 kcal, 5 to 6 minutes
• 500 m (20 lengths): about 100 kcal, 11 minutes
• 750 m (30 lengths): about 150 kcal, 16 minutes
• 800 m (32 lengths): about 160 kcal, 17 minutes
• 1,000 m (40 lengths): about 200 kcal, 22 minutes
• 1,200 m (48 lengths): about 245 kcal, 26 minutes
• 1,500 m (60 lengths): about 305 kcal, 33 minutes
• 1,600 m (64 lengths, roughly a mile): about 325 kcal, 35 minutes
• 2,000 m (80 lengths): about 405 kcal, 44 minutes
• 3,800 m, a full-distance triathlon swim: about 770 kcal, 1 hour 23 minutes
• 5,000 m: about 1,015 kcal, 1 hour 49 minutes

Distance figures hide a quirk. Fast crawl costs less per kilometre, about 180 kcal, than moderate or easy crawl at about 200, because the fast swimmer spends fewer minutes in the water even though each minute costs more. Worked example: a 62 kg swimmer does 1,500 m of moderate crawl. 1,500 m ÷ 46 m a minute = 32.6 minutes, or 0.54 hours. 8.0 × 62 × 0.54 = 268 kcal, which the calculator rounds to 270.

Distance mode only works for front crawl and race-effort open water, because the Compendium gives speeds only for crawl. For lengths of breaststroke or backstroke, time a few lengths and use time mode.

How the swimming calorie calculator works

The calculator multiplies a MET value for your stroke and effort by your weight in kilograms and the hours you swam: calories = METs × kg × hours. One MET is about 1 kcal per kilogram per hour, roughly what you burn sitting still. Calculated using MET values from the 2024 Adult Compendium of Physical Activities water activities list (4.8 to 13.8), the same dataset researchers use to grade exercise intensity.

In distance mode it converts metres to minutes with the Compendium's crawl speeds: slow crawl at 30 to 45 yards a minute (we use 34 m), medium at about 50 yards (46 m) and fast at about 75 yards (69 m). The open water settings use the Compendium's 6.0 METs for lake, sea or river swimming, which the Compendium marks as an estimate, not a measured value, and 10.5 METs for a 5 km open water race.

The result is gross calories, including what your body would burn at rest over the same time. For the extra cost of the swim, take off your weight × the hours: an hour of moderate crawl at 70 kg is 560 kcal gross and about 490 net.

Does cold water burn more calories?

Less than most people think, but it does make you hungrier. In a 2005 University of Florida study led by Lesley White, 11 students cycled for 45 minutes immersed in water at 20°C and, on another day, at 33°C. They burned almost the same in both (517 against 505 kcal), yet in the hour afterwards they ate 877 kcal after the cold session and 608 after the warm one, 44% more.

The study was small and the authors called it preliminary, but it is a useful correction. If you have seen cold water credited with burning about 40% more, that figure comes from what people ate afterwards, not what they burned. Long swims in water cold enough to make you shiver are a different case, and no MET-based calculator, this one included, models them.

What else changes your swimming calorie burn?

Technique is the factor a swimming calculator handles worst. An efficient swimmer covers more water per calorie, and MET values are population averages that cannot see your stroke. If your kilometre of crawl takes 30 minutes rather than 22, distance mode will assume you swam faster than you did, so use time mode with easy crawl instead.

In open water, sighting, chop and currents change your pace from one swim to the next, so time mode with the open water settings is the better choice there. Pick race effort only for swims where you were breathing hard throughout; most sea and lake swims belong on steady.

How to refuel after a swim

Calories first: an hour of steady crawl costs a 70 kg swimmer about 560 kcal, and for most pool sessions a normal meal within a couple of hours puts that back. You cannot eat in the pool, so the whole refuel lands afterwards, often when you are cold, hungry and some way from a kitchen.

A calorie-dense option in the kit bag helps. Our high calorie bars fit that gap: Phoenix Bars carry up to 557 calories in only 120g, about the cost of that hour of steady crawl, and can be stirred into water or milk to make a porridge after a swim. For long open water swims, where feeds during the swim start to matter, see our open water swimming nutrition guide, and if you are comparing options, the highest calorie bars in the UK ranked by calories per gram.

Frequently asked questions

How much swimming does it take to burn 1,000 calories? About 1 hour 47 minutes of continuous moderate front crawl for a 70 kg swimmer, or about 1 hour 22 minutes at a fast pace. By distance that is roughly 5 km at a moderate pace. Few people swim that long without stopping, so most 1,000 kcal swimming days are split across sessions.

How many calories does 50 minutes of swimming burn? About 465 kcal of moderate front crawl for a 70 kg swimmer, 350 kcal of gentle swimming and 310 kcal of recreational breaststroke. At a fast crawl it is about 615 kcal. Take off any time spent resting at the wall before you compare it with your watch.

Does swimming burn more calories than running? Not usually at a steady effort. The Compendium rates running at 6 mph (9.7 km/h) at 9.3 METs, about 650 kcal an hour at 70 kg, against 560 for moderate crawl. Fast crawl at 10.5 METs overtakes it. Our running calorie calculator works out runs, with a net figure too.

Does swimming burn more calories than walking? Yes, roughly twice as much per minute. Moderate front crawl rates 8.0 METs against 3.8 for walking at a normal 5 km/h, so an hour is about 560 kcal in the pool against 266 on foot for a 70 kg adult. The walking calorie calculator converts steps as well as time.

Why does my swim watch show a different number? Watches estimate from arm movement, stroke count and heart rate using their own models, while this calculator applies published MET values to your weight and time. Some watches report only active calories, which leave out resting burn, so compare them with the net figure rather than the gross one.

Working out other sports? Try our running calorie calculator, walking calorie calculator, cycling calorie calculator, hiking calorie calculator, ultra running calorie calculator and rucking calorie calculator.

Sources: 2024 Adult Compendium of Physical Activities, water activities and running MET values (Herrmann and colleagues, Journal of Sport and Health Science, 2024); University of Florida, Exercise in cold water may increase appetite (White and colleagues, International Journal of Sport Nutrition and Exercise Metabolism, 2005).

Written by James Frost, founder of Flaming Phoenix. Calculator method: 2024 Adult Compendium of Physical Activities. Updated October 2026.