Calories burned by an activity from its MET value in the Compendium of Physical Activities, your body weight and the time spent.
At 70 kg, 30 min of “walking, 3.5 mph, brisk” (4.3 MET) uses about 151 kcal, of which 116 kcal is above what you would burn at rest.
2011 Compendium code 17200: Walking, 3.5 mph, brisk = 4.3 MET.
1 MET = 1 kcal per kg per hour (Compendium definition). Displayed to the nearest kcal, rounded half-up.
Calories burned = MET × body weight in kg × hours. A MET (metabolic equivalent) is the energy cost of an activity as a multiple of resting, defined as 1 kcal per kg per hour or 3.5 mL of oxygen per kg per minute, and the values here come from the 2011 Compendium of Physical Activities. The result is also given in kilojoules, as calories above resting (MET − 1), and by the MET × 3.5 × kg ÷ 200 per-minute rule, which gives 5 % more.
People use it to log workouts and compare activities. A 70 kg person walking briskly at 3.5 mph (4.3 MET) for 30 minutes uses about 151 kcal, 116 kcal of it above resting; running at 6 mph for the same time uses 343 kcal.
MET values are averages measured in adults, so individual costs vary with fitness, technique and terrain. The resting value of 1 kcal per kg per hour is a convention: Byrne and colleagues (2005) measured an average of 0.84 in 769 adults.
Checked against: Python 3.8 decimal: 9.8 MET (2011 Compendium code 12050) × 70 kg × 0.5 h = 343 kcal; × 4.184 kJ/kcal
Checked against: Python 3.8 decimal: 4.3 MET (code 17200) × 68.0388555 kg × 0.75 h = 219.4253 kcal
Checked against: Compendium definition 1 MET = 1 kcal/kg/h → 80 kcal, 0 above rest; the 3.5 × 80 / 200 × 60 rule gives 84 kcal
Checked against: Python 3.8 decimal: 10.0 MET (code 01040) × 69.8532 kg × 1.5 h; net uses 9.0 MET
Multiply the activity's MET value by body weight in kilograms and by time in hours. Running at 6 mph is 9.8 MET in the 2011 Compendium, so a 70 kg runner uses 9.8 × 70 × 0.5 = 343 kcal in 30 minutes. The per-minute form, MET × 3.5 × kg ÷ 200, gives 5 % more because it takes 3.5 mL of oxygen per kg per minute at 5 kcal per litre of oxygen.
A metabolic equivalent is the energy used sitting at rest, conventionally 1 kcal per kg per hour or 3.5 mL of oxygen per kg per minute, and an activity's MET value is its cost as a multiple of that. The US Physical Activity Guidelines class 3.0–5.9 MET as moderate and 6 or more as vigorous, so brisk walking at 4.3 MET is moderate and running at 6 mph (9.8 MET) is vigorous.
About 4.3 kcal per kg of body weight per hour at a brisk 3.5 mph (Compendium code 17200), or 3.5 kcal at 2.8–3.2 mph. A 70 kg person walking briskly for 30 minutes uses about 151 kcal, 116 kcal of it above resting. A mile at 3.5 mph takes about 17 minutes, which works out at roughly 86 kcal per mile for that person.
MET values are group averages, and the resting value behind them is a convention. Byrne and colleagues (2005) measured resting energy use in 769 adults and found an average of 0.84 kcal per kg per hour, so the standard 1 kcal figure overstated rest by 20 %. Fitness, technique and terrain also change the cost, and the 2024 Adult Compendium revised 176 MET values as new measurements appeared.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “Running 6 mph for 30 minutes at 70 kg” is checked against Python 3.8 decimal: 9.8 MET (2011 Compendium code 12050) × 70 kg × 0.5 h = 343 kcal; × 4.184 kJ/kcal.
Ainsworth BE et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Med Sci Sports Exerc 2011;43(8):1575–1581; 2011 Compendium activity table (supplementary digital content 1); Compendium of Physical Activities — unit conversions (1 MET = 1 kcal/kg/h = 3.5 mL/kg/min).
4 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
Basal metabolic rate (BMR) by Mifflin-St Jeor, Harris-Benedict or Katch-McArdle, and daily calorie needs (TDEE) for five activity levels.
Daily calorie target for losing, maintaining or gaining weight, with macros in grams of protein, carbohydrate and fat per day and per meal.
Steps to distance in km and miles from a step length based on your height or measured, with walking time and calories from the ACSM equation.
Running pace per km or mile from distance and time, or finish time or distance from pace, with even splits and Riegel race predictions.
Heart rate zones from your maximum heart rate (220 − age, Tanaka, Gulati for women, or measured) by the Karvonen or percent-of-max method, with a target heart rate.
VO2 max from the Cooper 12-minute run, the Rockport 1-mile walk or the resting heart-rate ratio, rated against Cooper Institute norms for age and sex.
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