Estimate calories burned from your body weight, activity, and workout time using standard MET-based math with preset activities or a custom MET value.
How to use our Calories Burned Calculator
- Choose Weight unit, then enter Body weight using that same unit.
- Select Activity source. Use Preset activity for the built-in list, or choose Custom MET if you already know the MET value for your workout.
- Enter Activity or Custom MET, then type your Duration (minutes) using active exercise time.
- Click Calculate to see Estimated calories burned, Calories per minute, MET used, and the Intensity band.
- Sanity-check the result: if Calories per minute looks too high or low for your pace, confirm that your Activity, Custom MET, Body weight, and Duration (minutes) were entered correctly.
Definitions
Weight unit: The unit used for Body weight, either pounds or kilograms.
Body weight: Your current weight used in the calorie estimate. Higher body weight usually leads to a higher estimate for the same activity and time.
Activity source: The choice between a preset Activity and a user-entered Custom MET.
Activity: A built-in exercise or daily activity with a standard MET value from the Compendium of Physical Activities [1].
Custom MET: A MET value you enter yourself when you already know the intensity for your activity.
MET used: The metabolic equivalent value used in the math. About 1 MET is resting energy use, and higher MET values mean higher energy cost [2].
Estimated calories burned: The total estimated energy used during the activity, shown in kilocalories.
Calories per minute: The average calorie burn each minute during the session.
Intensity band: A simple category based on MET used: light under 3, moderate from 3 to 5.9, and vigorous at 6 or more [3].
Common mistakes and quick fixes
Mistake: Entering Body weight in kilograms while Weight unit is still set to pounds.
Fix: Match Weight unit to the unit you are using before you calculate.
Mistake: Counting total gym time in Duration (minutes) , including long rests or setup time.
Fix: Enter active exercise time only unless you want the whole session averaged together.
Mistake: Choosing a preset Activity that does not match your real pace, such as using running when you were walking.
Fix: Pick the closest pace-based Activity , or switch Activity source to Custom MET if you have a better MET value.
Mistake: Typing a guess into Custom MET without checking whether it matches your workout intensity.
Fix: Use Preset activity when possible, or enter Custom MET only when you have a reliable MET from a chart, class sheet, or study.
Mistake: Treating Estimated calories burned as an exact measurement.
Fix: Read it as a useful estimate and compare it with Calories per minute and MET used instead of expecting a perfect real-world number.
Mistake: Assuming the Intensity band tells you how hard the workout felt for every person.
Fix: Use Intensity band as a MET-based category only; your fitness level, terrain, and technique can make the same MET feel easier or harder.
Limitations & Key Assumptions / Boundary Conditions
- This calculator estimates exercise energy from MET, body weight, and time. It does not directly measure your personal calorie burn.
- Preset Activity values are averages. Real results can change with terrain, incline, water conditions, resistance, technique, and actual pace.
- The same MET used can feel very different across people because fitness level, movement efficiency, and body composition vary.
- Duration (minutes) should reflect active time. Including long rests lowers the average effort of the session and changes the estimate.
- When Activity source is set to preset, the hidden Custom MET is ignored. When set to custom, the hidden preset Activity is ignored.
- Custom MET must be realistic. Very low or very high values can produce misleading results even if the math still works.
- Wearables, treadmills, and lab testing may give different numbers because they use different sensors, equations, and assumptions.
Methodology
How the calculator works
This calculator uses the standard MET method for physical activity energy estimates. First it converts body weight to kilograms when needed, then it multiplies MET by body weight in kilograms and time in hours [1].
weight_kg = weight_lb x 0.45359237
duration_hr = duration_min / 60
calories_burned = MET x weight_kg x duration_hr
calories_per_min = calories_burned / duration_min
How MET is chosen
If you choose a preset Activity, the calculator uses that activity's stored MET value from the Compendium approach [1]. If you choose Custom MET, the calculator uses the value you enter and ignores the hidden preset activity.
The intensity label comes only from MET used.
if MET < 3, intensity_band = light
if MET >= 3 and MET < 6, intensity_band = moderate
if MET >= 6, intensity_band = vigorous
Worked example
Suppose you weigh 160 lb, choose Walking, 3.0 mph, and enter 30 minutes. The preset MET is 3.5.
weight_kg = 160 x 0.45359237 = 72.5748
duration_hr = 30 / 60 = 0.5
calories_burned = 3.5 x 72.5748 x 0.5 = 127.01
calories_per_min = 127.01 / 30 = 4.23
That means the session is estimated at about 127 kcal total, or about 4.23 kcal per minute. A higher MET, longer duration, or higher body weight increases the estimate.
Assumptions used
The method assumes about 1 MET equals about 1 kcal per kilogram per hour, which is a practical approximation used for activity estimates [2]. Preset activities use standard MET values, but real-world calorie burn can still differ because pace, incline, efficiency, body composition, and environment are not modeled here. This is why the result is best used as a planning estimate rather than an exact measurement.