Swimming Calorie Burn Calculator

This calculator estimates energy expenditure during swimming using the standard MET-based formula: Calories = MET × body weight (kg) × duration (hours). MET (Metabolic Equivalent of Task) quantifies the energy cost of physical activities relative to rest.

MET values are sourced from the 2024 Adult Compendium of Physical Activities, the standard reference used in exercise science. Different strokes and intensities produce very different MET values — butterfly at 13.8 MET burns far more calories than leisurely recreational swimming at 6.0 MET.

Optional adjustments account for open-water swimming (+5–10% due to sighting, navigation, currents, and wave resistance) and wetsuit use (−7% due to increased buoyancy reducing propulsion effort).

Pool swimming provides controlled conditions, consistent temperature, lane markers for pacing, and wall push-offs every 25–50 meters. Open-water swimming introduces sighting, navigation, currents, and waves, all of which increase energy expenditure even at the same perceived pace.

Triathletes should note that their race-day calorie burn in open water will typically be 5–15% higher than equivalent pool training, depending on conditions. Wetsuit buoyancy partially offsets this by reducing the energy needed for propulsion.