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Both calculators run independently — change the inputs on either side to compare results.
Heart Rate Zone Calculator
Calculate your personalised heart rate training zones using the Karvonen heart rate reserve method, which factors in resting heart rate to give zones that actually reflect your cardiovascular fitness. Used by coaches and endurance athletes to keep aerobic, threshold, and VO2-max sessions in the right intensity bands.
BMR / TDEE Calculator
Estimate your daily calorie needs using the revised Harris-Benedict equation, then adjust for activity to get your Total Daily Energy Expenditure (TDEE) — the rough number of calories you burn in 24 hours when you eat a maintenance diet. Enter your weight in kilograms, height in centimetres, age, biological sex, and an activity multiplier (sedentary 1.2, lightly active 1.375, moderately active 1.55, very active 1.725, extremely active 1.9). The result is what most nutrition guides call your "maintenance calories" — a starting point for designing a deficit (to lose weight), a surplus (to gain muscle), or a recomposition plan.
Key differences
| Heart Rate Zone Calculator | BMR / TDEE Calculator | |
|---|---|---|
| Category | Health | Health |
| Inputs required | 3 | 5 |
| Result | Heart Rate Training Zones (bpm) | Daily Calorie Needs (calories) |
| What it does | Calculate your personalised heart rate training zones using the Karvonen heart rate reserve method, which factors in resting heart rate to give zones that actually reflect your cardiovascular fitness. Used by coaches and endurance athletes to keep aerobic, threshold, and VO2-max sessions in the right intensity bands. | Estimate your daily calorie needs using the revised Harris-Benedict equation, then adjust for activity to get your Total Daily Energy Expenditure (TDEE) — the rough number of calories you burn in 24 hours when you eat a maintenance diet. Enter your weight in kilograms, height in centimetres, age, biological sex, and an activity multiplier (sedentary 1.2, lightly active 1.375, moderately active 1.55, very active 1.725, extremely active 1.9). The result is what most nutrition guides call your "maintenance calories" — a starting point for designing a deficit (to lose weight), a surplus (to gain muscle), or a recomposition plan. |