The number of calories burned while swimming varies widely depending on factors such as body weight, swim stroke, intensity, and duration.

• A 150-pound person swimming moderately burns about 400–500 calories per hour, and at high intensity, this can increase to 700–800 calories per hour

• A 180-pound individual burns approximately 475–570 calories per hour at moderate intensity and up to 950 calories at high intensity

• For lighter weights, a 125-pound woman burns about 180 calories in an hour, while a 155-pound woman burns around 216 calories, and a 185-pound woman burns about 252 calories

• Different strokes burn different amounts of calories: butterfly stroke burns the most, up to about 649–949 calories per hour depending on weight, followed by breaststroke and freestyle, with leisurely swimming burning fewer calories

• For a 150-pound person swimming freestyle laps at moderate effort, about 198 calories are burned in 30 minutes, while vigorous effort can burn 334 calories in 30 minutes

• Casual swimming burns fewer calories; for example, a 140-pound person burns around 233 calories per hour swimming casually, and moderate speed swimming burns about 520 calories per hour

In summary, swimming can burn roughly 250 to 950 calories per hour depending on your weight, swim stroke, and effort level. The butterfly stroke and vigorous freestyle laps burn the most calories, while leisurely swimming burns fewer calories