Calories Burned by Heart Rate Calculator
The calories a workout burned from your average heart rate, its length, and your age, weight and sex — the formula fitness watches use when they have no power or pace data.
Heart rate tracks oxygen uptake during steady exercise, and oxygen uptake tracks energy.
How the calories burned by heart rate calculator works
Heart rate tracks oxygen uptake during steady exercise, and oxygen uptake tracks energy. The Keytel equations, fitted to lab measurements, give calories per minute from heart rate, weight, age and sex; multiplying by the minutes gives the session. They are reasonable between about 90 and 150 beats per minute in steady aerobic exercise, and less so for interval work or for very fit or unfit people.
Formula: men: kcal/min = (−55.0969 + 0.6309·HR + 0.1988·kg + 0.2017·age) ÷ 4.184; women: (−20.4022 + 0.4472·HR − 0.1263·kg + 0.074·age) ÷ 4.184
Worked examples
| Inputs | Calories burned | Note |
|---|---|---|
| Man, 35, 80 kg, 150 bpm for 45 minutes | 672 kcal | 672 kcal |
| Woman, 30, 62 kg, 140 bpm for 60 minutes | 525 kcal | 512 kcal |
| Man, 50, 175 lb, 130 bpm for 30 minutes | 378 kcal | 363 kcal |
FAQFrequently asked questions
How accurate is this?
Within about 10–15% for steady aerobic exercise in the middle heart-rate range; the equations were fitted to a group of healthy adults. A watch with VO₂ max data, or a power meter, does better.
Why does my watch give a different number?
Watches use their own versions with your measured VO₂ max or resting heart rate, and some add the after-burn. Differences of 20% between devices are normal.
Does it work for intervals?
Poorly. Heart rate lags effort and stays high in recoveries, and sprints burn energy the heart-rate relationship does not capture. Use the average over the session and expect an underestimate.
Does this include what I would have burned anyway?
Yes — it is gross calories for the time, including your resting metabolism. Net exercise calories are about 1–1.5 kcal a minute less.
Where these figures come from
- Riegel PS, "Athletic records and human endurance", American Scientist 1981 — T2 = T1 × (D2 ÷ D1)^1.06
- Cooper KH, "A means of assessing maximal oxygen intake", JAMA 1968 — the 12-minute run test
- Ainsworth BE et al., Compendium of Physical Activities (2024 update) — MET values by activity
- OpenPowerlifting — DOTS coefficients (Tim Konertz, 2019) — the DOTS polynomial used for scoring
- Naismith's rule (1892) as used by UK and Australian walking bodies — 1 hour per 5 km plus 1 hour per 600 m of ascent
- UK Sport — national high-performance body
Last checked: September 2026. Formulas are fixed by their published sources; the MET values come from the Compendium of Physical Activities.