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Accepted range: 20–350 kg equivalent.
Presets use the 2024 Adult Compendium; choose Custom MET only for a trusted value.
Accepted range: 0.5–25.0 MET.
MET
Accepted range: 1 minute through 24 hours.
Keep the same model when comparing sessions.
Accepted range: 0.50–1.50.
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A planning target from 1–10,000 kcal; this is not a nutrition or safety recommendation.
kcal
Use 1–14 comparable sessions for the weekly planning rows.
sessions
MeasureEstimateUseCopy
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Calorie targetTotal timeDifference from sessionCopy
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A calorie-burn estimate turns a session into an energy value by combining body mass, activity intensity, and time. It is useful for comparing similar workouts or planning a target, but it is not a direct measurement. Laboratory methods can measure oxygen use; everyday estimates usually assign a standard energy cost to the activity instead.

That standard is the metabolic equivalent of task, or MET. One MET represents the conventional resting energy cost. A 4-MET activity is modeled at four times that baseline and an 8-MET activity at eight times the baseline. The activity description matters because pace, slope, resistance, and effort can move two sessions with the same broad name into different MET values.

  • Gross calories include the resting 1-MET portion during the session.
  • Active calories estimate only the energy above that resting portion.
  • Absolute intensity comes from the MET value, not from how hard the session felt to one person.
  • Comparable sessions should use the same MET source, duration convention, and calculation model.

Body mass and duration scale the arithmetic directly. A longer session or a higher body mass produces a larger estimate when MET stays fixed. Real energy use can still differ with fitness, movement economy, terrain, weather, carried load, technique, rest periods, and individual resting metabolism.

Use calorie estimates as a planning range rather than a food allowance or measure of workout quality. Training benefit also depends on intensity, recovery, progression, and the purpose of the session. Health, rehabilitation, pregnancy, injury, or major nutrition decisions need advice tailored to the individual.

How to Use This Tool:

Describe one session and keep the same estimate model when comparing it with another.

  1. Enter Weight in kilograms or pounds and choose the closest Activity for the actual pace or effort.
  2. Use Custom MET only when a trusted source supplies a value that fits the session more closely than a preset.
  3. Enter Duration in minutes or hours. Use active or moving time when long breaks would make elapsed time misleading.
  4. Choose an Estimate model. Keep that choice fixed across comparisons because the 1.00, 1.05, or custom multiplier changes every calorie result.
  5. Set Target burn and Sessions per week only when you need target timing or weekly planning rows, then compare Gross session burn with Active-only burn.

Interpreting Results:

Estimated session burn is the gross calorie value. Use Active-only burn when the question is how much exercise energy was added above rest. Neither figure measures an individual session with wearable or laboratory data.

The intensity label follows exact MET boundaries. Values below 3.0 MET are light, values from 3.0 up to but not including 6.0 are moderate, and 6.0 MET or higher are vigorous. Moderate-equivalent minutes count moderate time once and vigorous time twice; light time receives no credit in that specific weekly result.

Time to target assumes the same MET, mass, and model factor continue for the full duration. Before acting on a surprisingly high or low number, verify the activity pace and whether duration includes long rests. A precise decimal does not remove the uncertainty in the MET assignment.

Technical Details:

Standard MET values express activity energy cost relative to the conventional 3.5 mL of oxygen per kilogram per minute baseline. Multiplying that oxygen rate by about 5 kcal per liter and converting minutes to hours gives a factor of 1.05. The quick model uses 1.00 instead, while the custom path accepts a factor from 0.50 to 1.50.

Formula Core:

After pounds are converted to kilograms and time is converted to hours, gross and active estimates use the same linear structure.

Cgross = MWHF Cactive = max(M-1,0)WHF ttarget = CtargetMWF×60

M is the selected MET value, W is body mass in kilograms, H is duration in hours, and F is the model factor. Calories are expressed as kilocalories, and target time is returned in minutes.

For a 70 kg person running at the 8.5-MET preset for 30 minutes with the 1.05 factor, gross burn is 312.375 kcal and active burn is 275.625 kcal before display rounding. The gross rate is 624.75 kcal per hour, so a 500 kcal target takes about 48.0 minutes under unchanged conditions.

Rule Core:

Rule Boundary Result
Weight20 to 350 kg after conversionPounds use 0.45359237 kg per pound.
Duration1 minute through 24 hoursHours are converted to minutes before the session result is stored.
Custom MET0.5 to 25.0Used only when the custom activity path is selected.
LightMET < 3.0Zero moderate-equivalent minutes.
Moderate3.0 ≤ MET < 6.0Minutes count once.
VigorousMET ≥ 6.0Minutes count twice.

All calculations keep full floating-point precision. Gross and active session values display one decimal place, rates may use one or two decimals, and target durations are formatted as readable time. Weekly totals multiply the unrounded session values by 1 to 14 sessions.

Limitations:

Compendium MET values standardize activity estimates; they do not capture one person's metabolism with clinical precision. The 2024 Adult Compendium is aimed at adults aged 19 to 59 and notes limits for older adults and people with conditions that materially affect energy expenditure.

  • Intervals, field sports, strength circuits, and stop-and-go sessions may not fit one steady MET value.
  • Resting metabolism, body composition, fitness, terrain, equipment, temperature, and technique can shift actual energy use.
  • A calorie target is not a nutrition recommendation or a safety limit.
  • Use individualized clinical or sports guidance for pregnancy, chronic disease, rehabilitation, injury, or major changes in diet and training.

References: