How Calories Burned Is Calculated

概要

This calculator estimates how many calories you burn during physical activity using MET (Metabolic Equivalent of Task) values from the 2011 Compendium of Physical Activities (Ainsworth et al., 2011). MET is a standardised measure of exercise intensity: 1 MET equals the energy cost of sitting quietly, roughly 1 kcal per kilogram of body weight per hour.

仕組み

Every physical activity has a MET value that represents how many times more energy it requires compared to rest. Walking briskly (4.8 MET) burns 4.8 times more energy than sitting; running at 8 km/h (8.3 MET) burns 8.3 times more. The calculator multiplies this intensity factor by your body weight and the duration of the activity.

MET definition

By convention, 1 MET is defined as:

• 1 kcal/kg/hour — the energy cost at rest
• 3.5 mL O₂/kg/min — the resting oxygen consumption rate (Jetté et al., 1990)

These two definitions are approximately equivalent. The first (1 kcal/kg/hr) is the one used in this calculator for its simplicity.

計算式

Alternative formula (ACSM)

Some calculators use the ACSM (American College of Sports Medicine) formula derived from oxygen consumption:

kcal/min = MET × 3.5 × weight (kg) ÷ 200

This gives results approximately 5% higher because the VO₂-to-kcal conversion (1 L O₂ ≈ 5 kcal) produces 1.05 kcal/kg/hr per MET rather than exactly 1.0. Both approaches are standard in exercise science. Our calculator uses the simpler Compendium convention.

Sample MET values

計算例

入力値の説明

• Body weight — your weight in kg or lbs. Heavier people burn more calories for the same activity because they are moving more mass.
• Duration — how long you performed the activity in minutes.
• Activity — choose from 40+ activities grouped by category. Each activity has a specific MET value from the Compendium.

出力値の説明

• Total calories burned — the estimated total energy expenditure for the selected activity
• Calories per minute — total calories divided by duration, useful for comparing activities
• MET value — the metabolic intensity of the selected activity
• Food equivalents — how the calorie burn compares to common food items (e.g. slices of pizza, pints of beer)
• Activity comparison — how many calories other common activities would burn in the same duration

前提条件と制限事項

• MET values are population averages. They were measured on groups of healthy adults and may not reflect your individual energy expenditure. Actual calorie burn varies with fitness level, body composition, age, and genetics.
• The 1 MET = 1 kcal/kg/hr convention was derived from a 40-year-old, 70 kg male (Jetté et al., 1990). Your resting metabolic rate may differ by 10–20%.
• Constant intensity assumed. MET values assume the activity is performed at a steady pace. Interval training or variable effort is not captured.
• Net vs. gross calories. This calculator reports gross calories (total burned including resting metabolism). To get net calories (extra burned above rest), subtract your BMR for the same duration.
• Not a substitute for wearable devices. Heart rate monitors and fitness trackers provide more individualised estimates by accounting for real-time exercise intensity.

検証