BMR Calculator
Calculate your Basal Metabolic Rate — the calories your body burns at complete rest — and see daily calorie needs for every activity level.
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest, just to stay alive — running your heart, lungs, brain, and the constant repair of your cells. It is the single biggest part of your daily calorie burn, usually 60–70% of the total.
How BMR is calculated
This calculator uses the Mifflin-St Jeor equation, which research has found to be the most accurate for most people:
- Men:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 - Women:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
For example, a 30-year-old man who is 180 cm and 80 kg has a BMR of about 1,780 kcal/day — the energy he would burn lying in bed all day.
From BMR to daily calories
You never actually burn just your BMR, because you move. Multiplying BMR by an activity factor gives your total daily calorie needs — shown in the table beside the calculator for each activity level, from sedentary to very active. That total is your TDEE, the number to eat around to maintain your weight.
What affects your BMR
BMR rises with more muscle mass and body size, and falls gradually with age as muscle is lost. Sex matters too — men usually have a higher BMR than women of the same size because they carry more muscle. Because BMR is an estimate, use it as a baseline and adjust based on how your weight actually behaves over time.
Frequently asked questions
What is BMR?
Basal Metabolic Rate is the number of calories your body burns just to keep you alive at complete rest — powering your heart, brain, breathing, and cell repair. It typically accounts for 60–70% of the calories you burn each day.
What is the difference between BMR and TDEE?
BMR is your calorie burn at rest. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor, so it includes the calories you burn moving, exercising, and digesting food. TDEE is always higher than BMR.
How can I increase my BMR?
The biggest lever is muscle mass — muscle is more metabolically active than fat, so resistance training gradually raises BMR. Staying well-fed (rather than crash dieting), sleeping enough, and staying active also help protect it.