BMR Calculator
Calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation.
| Activity Level | Estimated Daily Calories |
|---|---|
| Sedentary (little/no exercise) | 2,011 kcal/day |
| Light (1-3 days/week) | 2,305 kcal/day |
| Moderate (3-5 days/week) | 2,598 kcal/day |
| Active (6-7 days/week) | 2,891 kcal/day |
| Very active (hard exercise + physical job) | 3,185 kcal/day |
Your BMR of 1,676 kcal/day is what you'd burn lying still all day — multiply it by an activity factor above to estimate your total daily burn.
This is calories burned at complete rest. See the Calorie Calculator to include activity level.
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BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + (5 for men, −161 for women)
About the BMR Calculator
Basal Metabolic Rate is the energy your body burns just to stay alive — running your heart, keeping your lungs breathing, repairing cells, regulating temperature — if you did nothing but lie still for 24 hours. It's not what you burn in a normal day; it's the floor underneath it, before you add a single step of walking or a single flight of stairs.
This calculator uses the Mifflin-St Jeor equation, which replaced the older Harris-Benedict formula in most clinical and nutrition settings because it's been shown to estimate resting energy expenditure more accurately across a broad population. Like any formula built from population averages, though, it's an estimate — genetics, thyroid function, muscle mass and even sleep quality can shift someone's real BMR up or down from what the equation predicts.
People mostly reach for a BMR number as the starting point for a calorie target, whether they're cutting, bulking or just curious what their body needs at rest. Because it only takes your height, weight, age and sex, and none of it leaves your device, it's also a fast way to check the number without creating an account on a diet-tracking app first.
How it’s calculated
Mifflin-St Jeor: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5 for men, or −161 for women. The weight and height terms capture body size, the age term reflects that metabolism gradually slows with age, and the final sex-based constant adjusts for the fact that, on average, men carry more muscle mass relative to their height and weight than women do — and muscle is metabolically more active at rest than fat tissue.
The table below multiplies your BMR by a set of standard activity factors, since almost nobody actually spends a whole day at complete rest — that gives you a rough total daily burn to compare against, which the Calorie and TDEE calculators build on further.
Frequently asked questions
What's the difference between BMR and TDEE?
BMR is calories burned at complete rest; TDEE (Total Daily Energy Expenditure) adds in movement, exercise and digestion on top of BMR. BMR is the floor, TDEE is closer to what you actually burn in a real day.
Why do men and women have different BMR formulas?
The Mifflin-St Jeor equation adds a flat +5 for men and −161 for women to account for typical differences in body composition — men tend to carry more lean muscle mass at a given height and weight, and muscle burns more calories at rest than fat.
How can I raise my BMR?
Building muscle through resistance training is the most reliable lever, since muscle tissue burns more energy at rest than fat tissue. Crash dieting tends to do the opposite — it can lower BMR as the body adapts to reduced intake.
Is Mifflin-St Jeor more accurate than Harris-Benedict?
Generally yes — most modern nutrition guidelines favor Mifflin-St Jeor because studies have found it estimates resting energy expenditure more accurately for most people than the older Harris-Benedict formula from 1919.
Should I eat exactly my BMR to lose weight?
No — eating at or below your BMR ignores the energy you burn through daily activity and can be an unnecessarily aggressive deficit. Use the Calorie Calculator, which factors in activity level, for a more realistic target.
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