How many calories does swimming burn in 30 minutes?

A 70 kg person swimming moderate freestyle for 30 minutes burns approximately 850 kJ (203 kcal). Butterfly at moderate pace burns about 1,440 kJ (345 kcal) - nearly twice as much.

Which swimming stroke burns the most calories?

Butterfly burns the most energy due to the intense full-body movement. At moderate intensity, butterfly burns 9.8 METs compared to 5.8 for freestyle, 5.3 for breaststroke, and 4.8 for backstroke.

How many kilojoules does 1 km of swimming burn?

For a 70 kg person swimming freestyle at moderate pace, 1 km takes about 20-25 minutes and burns approximately 570-710 kJ (136-170 kcal). Slower swimmers burn fewer kJ per km but more per minute of swimming.

Swimming Calorie Calculator

Swimming is a full-body workout that burns significant energy. This calculator estimates kilojoules and calories burned based on your stroke type, intensity level, body weight, and swim duration.

Enter Your Details

Body Weight

Stroke

Intensity

Duration

min

How It Works

Swimming energy varies by stroke and intensity. Freestyle moderate = 5.8 METs, backstroke = 4.8, breaststroke = 5.3, butterfly = 9.8 METs. Energy (kJ) = MET × weight (kg) × hours × 4.184.

Quick Reference

Stroke	Intensity (MET)	kJ / 30 min	kcal / 30 min
Freestyle	Light (4.8)	904	216
Freestyle	Moderate (5.8)	1,093	261
Freestyle	Vigorous (9.8)	1,846	441
Backstroke	Moderate (4.8)	904	216
Breaststroke	Moderate (5.3)	998	239
Butterfly	Moderate (9.8)	1,846	441
Butterfly	Vigorous (13.8)	2,599	621

Based on 75 kg body weight, 30 minutes duration.

Frequently Asked Questions

How many calories does swimming burn in 30 minutes?: A 70 kg person swimming moderate freestyle for 30 minutes burns approximately 850 kJ (203 kcal). Butterfly at moderate pace burns about 1,440 kJ (345 kcal) - nearly twice as much.
Which swimming stroke burns the most calories?: Butterfly burns the most energy due to the intense full-body movement. At moderate intensity, butterfly burns 9.8 METs compared to 5.8 for freestyle, 5.3 for breaststroke, and 4.8 for backstroke.
How many kilojoules does 1 km of swimming burn?: For a 70 kg person swimming freestyle at moderate pace, 1 km takes about 20-25 minutes and burns approximately 570-710 kJ (136-170 kcal). Slower swimmers burn fewer kJ per km but more per minute of swimming.

How This Is Calculated

kcal = MET × weight (kg) × duration (hours)

MET: = Metabolic Equivalent - varies by stroke and intensity (3.5–13.8)
weight: = body weight in kilograms

Freestyle: 4.8/5.8/9.8, Backstroke: 3.5/4.8/7.0, Breaststroke: 3.5/5.3/8.0, Butterfly: 6.0/9.8/13.8 (light/moderate/vigorous).

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Disclaimer

This calculator provides estimates for informational purposes only and should not be considered medical advice. Individual results may vary based on factors not captured by these formulas. Consult a healthcare professional before making changes to your diet or exercise routine, especially if you have any existing health conditions.