BMR Calculator.
Estimate your basal metabolic rate - the calories your body burns at complete rest - using the Mifflin-St Jeor equation. Enter your sex, age, height, and weight to get your BMR in calories per day. It is the starting point for any calorie target.
Calculate your BMR
the short answer
A BMR calculator estimates basal metabolic rate using the Mifflin-St Jeor equation: men, BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5; women, the same minus 161. It returns the calories you burn at complete rest. Multiply BMR by an activity factor to get your TDEE - the number you eat around to lose, maintain, or gain weight.
What is BMR and how is it calculated?
Your basal metabolic rate (BMR) is the number of calories your body burns at complete rest just to stay alive - breathing, circulating blood, repairing cells, and keeping your organs running. It is the single largest part of how many calories you burn in a day, usually 60 to 70 percent, before any movement or exercise is added.
This calculator uses the Mifflin-St Jeor equation, the formula most dietitians consider the most accurate for the general population. In metric units it is: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5 for men, and the same with - 161 instead of + 5 for women. The only difference between the two is that final constant, which reflects average differences in body composition. If you enter imperial units, the tool converts your weight to kilograms and height to centimetres internally before running the formula, so the math is identical either way.
The result is an estimate, not a lab measurement. True metabolic rate varies with muscle mass, hormones, and genetics, so treat your BMR as a smart, repeatable starting point rather than a fixed number.
BMR vs TDEE: which number do you eat around?
BMR is only the resting number. The number you actually plan your eating around is your TDEE - total daily energy expenditure - which is your BMR multiplied by an activity factor that accounts for daily movement, exercise, and the energy used to digest food. Your TDEE is always higher than your BMR.
Once you know your TDEE, you set a target on top of it: a calorie deficit for fat loss, maintenance to hold steady, or a surplus for muscle gain. Eating consistently far below your BMR is rarely sustainable, so your BMR works well as a sensible floor when you plan intake.
To turn your BMR into a usable daily target, run it through our TDEE calculator, then set a goal-based calorie number with the calorie calculator.
How coaches use a BMR calculator.
For online fitness and nutrition coaches, BMR is the first input when setting a client's calorie target. The workflow is consistent: estimate BMR from the client's stats, scale it to TDEE with an activity factor, then add a deficit or surplus that matches the goal. Doing this the same way for every client keeps targets defensible and easy to adjust at the next check-in.
The harder part is keeping those numbers attached to a real plan. If you coach a full list of clients, learning how to become an online fitness coach and how to price your coaching packages are the next steps once you have your nutrition method down.
Set targets like this for every client - automatically.
A calculator gives you one number. Coachway lets coaches set per-client calorie and macro targets and track them alongside training in one place, so the number turns into an actual plan your clients follow in their own branded app. See how the meal planner handles the nutrition side.
See Coachway pricingFrequently asked questions.
What is a BMR calculator?
A BMR calculator estimates your basal metabolic rate - the number of calories your body burns at complete rest to keep vital functions running, like breathing, circulation, and cell repair. This one uses the Mifflin-St Jeor equation, the formula most dietitians trust, taking your sex, age, height, and weight to return an estimated BMR in calories per day.
What is the formula for BMR?
The Mifflin-St Jeor BMR formula is: for men, BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5; for women, BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161. The only difference between the two is the final constant, +5 for men and -161 for women, which reflects average body-composition differences.
What is the difference between BMR and TDEE?
BMR is the calories you burn at complete rest. TDEE - total daily energy expenditure - is BMR multiplied by an activity factor to account for movement, exercise, and digestion. Your TDEE is always higher than your BMR and is the number you actually eat around to lose, maintain, or gain weight. Use a TDEE calculator to apply your activity level.
Is the Mifflin-St Jeor BMR formula accurate?
The Mifflin-St Jeor equation is widely regarded as the most accurate predictive BMR formula for the general population, which is why dietitians favour it over older equations like Harris-Benedict. It is still an estimate - true metabolic rate varies with muscle mass, hormones, and genetics - so treat the result as a smart starting point, not a precise lab measurement.
Why does BMR matter for fat loss or muscle gain?
Your BMR is the foundation of any calorie target. Once you know roughly how many calories you burn at rest, you can build a realistic deficit for fat loss or a surplus for muscle gain on top of your TDEE. Eating far below your BMR for long stretches is rarely sustainable, so it acts as a sensible floor when planning intake.
How do coaches use a BMR calculator?
Coaches use BMR as the first input when setting a client calorie target. They estimate BMR, scale it to TDEE with an activity factor, then add a deficit or surplus that matches the goal. On a coaching platform like Coachway, these targets are set per client and tracked alongside their training, so the number turns into an actual plan rather than a one-off figure.
This calculator is general information, not medical or dietary advice. Estimated values are a starting point, not a substitute for guidance from a qualified professional.
Keep going: turn your BMR into a daily target with the TDEE calculator and the calorie calculator, or read our guides on becoming an online fitness coach and pricing online coaching packages.
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Open calculator ->See what Coachway can do for your coaching business
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