About the Calorie Calculator
A calorie calculator estimates the number of calories you should consume each day to maintain, lose, or gain weight. It combines BMR (the energy needed at rest) with an activity multiplier to produce TDEE (total daily energy expenditure).
Assumptions
- BMR uses Mifflin-St Jeor — accurate within ~10% for most healthy adults.
- Activity multipliers are population averages; individual variation is meaningful.
- Weight-loss recommendations assume ~3,500 kcal per pound of fat — a useful approximation, not a physical constant.
- Adaptive thermogenesis (the body's response to extended deficits) is not modeled.
Formula
TDEE = BMR × activity factor
- BMR = Basal metabolic rate (Mifflin–St Jeor)
- activity factor = 1.2 (sedentary) to 1.9 (very active)
Frequently asked questions
How accurate is this estimate?
TDEE formulas are typically within ±10% for healthy adults. Track your actual weight trend over 2–3 weeks and adjust intake by ±200–300 kcal/day if weight changes aren't matching your goal.
How many calories to lose weight?
A safe loss is 0.5–1 lb per week, requiring a ~500 kcal daily deficit from maintenance. Cutting more than 20% below TDEE risks muscle loss and adherence issues.
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