Calories burned,
across 59+ workouts.

Field guide

How calories burned during exercise are calculated.

The standard equation, used by most fitness wearables and every published academic calculator, is:

Pull the three numbers, multiply, done. The art is in picking the right MET value and understanding what the output represents.

What is a MET?

One MET is the energy cost of sitting quietly: roughly 1 kcal per kilogram of body weight per hour, or equivalently 3.5 mL of oxygen per kg per minute. Walking briskly is about 4.3 MET: over four times resting. Running a 6-minute mile is 14.5 MET: over fourteen times resting, though most people can only sustain that for a few minutes.

Worked example

A 175-pound (79.4 kg) runner doing 30 minutes at a 10-min/mile pace (6 mph, MET 9.8):

That's the gross burn — it includes the calories you'd have burned at rest during those 30 minutes. Thenet activity burn subtracts resting expenditure (1 MET × kg × hours = 39.7 kcal) for 389 − 40 ≈ 349 kcal. Most consumer apps quote the gross number; clinical and research contexts often quote net. The calculator surfaces both.

Gross vs. net burn, which should you use?

For weight-management math, gross is the number you want. Your body's overall energy budget treats workout calories and resting calories the same way. If you track maintenance calories via TDEE that already includes rest, you'd subtract resting metabolism from the workout estimate to avoid double-counting; otherwise, just use gross.

Where MET values come from

The values used here are from the Compendium of Physical Activities(Ainsworth et al., 2011), the standard academic reference, updated periodically since 1993. Each MET value is the average energy cost of an activity measured against resting baseline across multiple study populations. Individual variation runs about ±10–15% from the published value, mostly from differences in metabolic efficiency, fitness level, and movement economy.

Why your fitness watch may disagree

• Watches often use heart-rate-based estimates(which add personal-fitness adjustments) rather than pure MET.
• Many watches add a sedentary-baseline subtraction by default, i.e. they show net while the compendium gives gross.
• Walking and low-intensity activity is where consumer wearables disagree most; they tend to over-estimate short bursts and under-estimate steady moderate effort.

Limitations of the linear MET model

• Body composition. MET scales linearly with body mass, but a heavier person at 14 MET is doing more total work than the lean equivalent — the model holds well up to ~10 MET, then becomes less reliable for high-intensity sustained effort.
• Fitness level. A trained athlete is more metabolically efficient and may burn slightly fewer calories at the same workload.
• Environmental factors. Heat, cold, wind, elevation, and terrain all shift real-world burn versus the lab MET value the activity was measured in.

Disclaimer

Estimates are accurate to roughly ±15% for the typical adult; treat any individual figure as a planning guide, not a precise meter. For weight-management decisions, what matters more than the exact number is directional consistency, using the same method week-over-week so trends are real.