Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
One Rep Max Calculator
Predict your one-rep max (1RM) — the heaviest weight you could lift for a single perfect rep — from a recent set you actually performed. Used by powerlifters, strength coaches, and bodybuilders to prescribe percentage-based training (e.g., "work up to 5×5 at 80% of 1RM") without the risk and recovery cost of repeatedly testing true maxes.
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
| One Rep Max Calculator | BMR / TDEE Calculator | |
|---|---|---|
| Category | Fitness | Health |
| Inputs required | 4 | 5 |
| Result | Estimated 1RM (kg) | Daily Calorie Needs (calories) |
| What it does | Predict your one-rep max (1RM) — the heaviest weight you could lift for a single perfect rep — from a recent set you actually performed. Used by powerlifters, strength coaches, and bodybuilders to prescribe percentage-based training (e.g., "work up to 5×5 at 80% of 1RM") without the risk and recovery cost of repeatedly testing true maxes. | 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. |