BMR & TDEE Calculator
Your basal metabolic rate from the Mifflin-St Jeor equation, your total daily energy expenditure at your activity level, and sensible calorie targets either side of it.
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How it works
BMR uses the Mifflin-St Jeor equation — 10 × weight + 6.25 × height − 5 × age, plus 5 for men or minus 161 for women — which validation studies consistently find closest to measured resting burn for most adults, usually within about 10%. TDEE then multiplies by an activity factor. That multiplier is the least precise part of the whole calculation: two people who both call themselves “moderately active” can differ by 400 kcal a day.
The loss target subtracts 500 kcal, the classic deficit for roughly 0.45 kg per week. Treat the first fortnight as calibration: if your weight trend ignores the prediction, your true TDEE is not where the equation put it, and the trend wins.
Good practice & limits
- Judge by the 3-week weight trend, never by single weigh-ins — water alone swings 1–2 kg.
- If you track exercise with a watch, do not also pick a high activity factor. That is counting the same burn twice.
- Protein at the upper end of the range while dieting protects the muscle you want to keep.