Calories Burned by Heart Rate Calculator
Estimate a session's energy burn from your average heart rate, the same published model many wearables build on.
- 1 cited source
- Calculates in your browser
Your answer
Appears here as you enter your details. No demo figures — the number is yours, or it is nothing.
Baseline
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BMI, resting rate, daily burn, eating target, macros, body fat, waist ratios, heart-rate zones and your fitness age: 15 in all. Answer once, see them together, and stop whenever you like.
Get my Baseline →Methodology
The estimate uses the Keytel et al. (2005) equations, developed on 115 regularly-exercising adults during steady cycling and treadmill work against measured oxygen consumption:
- Men:
kJ/min = −55.0969 + 0.6309 × HR + 0.1988 × weight (kg) + 0.2017 × age - Women:
kJ/min = −20.4022 + 0.4472 × HR − 0.1263 × weight (kg) + 0.074 × age
Kilojoules convert to kilocalories at 4.184, and the per-minute rate is multiplied by your session duration. These are the equations (without the VO2max term) that much of the consumer heart-rate industry builds on.
Interpreting your result
The relationship between heart rate and energy expenditure is close to linear during steady aerobic exercise, that's the model's home ground. Use your session-average heart rate from a strap or watch, and treat the output as a consistent estimate for comparing your own sessions rather than a measurement.
Fitness shifts the line: a fitter person burns more at the same heart rate than the population average predicts (the published model with a VO2max term corrects for this; the version here deliberately needs no lab value).
Limitations
- Valid for steady aerobic work at roughly 90 bpm upwards, the tool warns rather than reporting numbers below that.
- Interval sessions blur the average; the estimate degrades as work becomes less steady.
- Resistance training raises heart rate out of proportion to oxygen use, so heart-rate estimates overshoot badly there, use the MET-based calculator instead.
- Stress, heat, dehydration and caffeine all raise heart rate without raising energy expenditure.
Sources
Pull the receipts, 1 cited source
FitTools · sources
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Frequently asked questions
- How does heart rate estimate calories burned?
- During steady aerobic exercise, heart rate rises roughly linearly with oxygen use, and oxygen use maps to energy expenditure. The Keytel equations capture that relationship from sex, age, weight and heart rate, no VO2max test needed.
- How accurate is this estimate?
- Group-level accuracy is good for steady cardio, but individual error can be meaningful, fitness level shifts the heart-rate/energy relationship. Treat the number as a consistent estimate for comparing your own sessions, not a precise measurement.
- Why does it need my average heart rate?
- The model assumes a steady working heart rate, so use the session average from your watch or chest strap. For intervals the average blurs the picture, the estimate degrades as work gets less steady.
- Why does the calculator warn at low heart rates?
- The equations were developed on exercise at roughly 90 bpm and above; below that the linear fit breaks down (it can even go negative), so numbers in that region aren't meaningful and we say so rather than showing one.
- Does this work for weight training?
- Poorly, lifting spikes heart rate for reasons other than oxygen demand (pressor response), so heart-rate-based estimates overshoot. The MET-based calories-burned calculator is the better tool there.
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