We estimate your calorie burn based on your heart rate, age, weight, height, gender and workout duration. The number you see combines calories burned during the session and a small "afterburn" effect from high-intensity effort.
💡Important: Calorie estimates – at BEAT81 or anywhere else – are approximations, not exact measurements. Individual variation can be significant. Use them as a general indicator of effort, not a precise target. How you feel during and after the workout is always a better guide than any number.
Want the details? Here's how we calculate it:
We use two established formulas:
- Keytel formula – estimates calories burned during exercise based on heart rate
- Harris-Benedict formula – calculates your basal metabolic rate (calories burned at rest)
We subtract your resting calorie burn from your gross exercise burn to get your net workout calories. We then add an afterburn estimate (EPOC) based on time spent above 80% of max heart rate.
Full formulas (if you're deep into this stuff):
Keytel Formula (Gross Calorie Burn):
Male:
(-55.0969 + 0.6309 × average heart rate + 0.1988 × weight + 0.2017 × age) / 4.184 × 60 × durationInHours
Female:
(-20.4022 + 0.4472 × average heart rate - 0.1263 × weight + 0.074 × age) / 4.184 × 60 × durationInHours
Harris-Benedict Formula (Basal Metabolic Rate, calories per 24 hours):
Male:
13.75 × weight + 5 × height - 6.76 × age + 66
Female:
9.56 × weight + 1.85 × height - 4.68 × age + 655
Resting Metabolic Rate for workout duration:
Basal metabolic rate × 1.1 / 24 × durationInHours
Net calorie burn:
Gross calorie burn - Resting metabolic rate calorie burn
EPOC (Afterburn) Calculation:
- Trained above 80% for less than 8.5 minutes → EPOC = Workout calories × 0.20
- Trained above 80% for 8.5–16.5 minutes → EPOC = Workout calories × 0.25
- Trained above 80% for more than 16.5 minutes → EPOC = Workout calories × 0.20
Total calories = Workout calories + EPOC calories