BMR Calculator
Estimate daily calorie burn with the Mifflin-St Jeor equation.
Free BMR calculator using the Mifflin-St Jeor equation. Enter age, sex, height, weight and activity level to get BMR and TDEE estimates.
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About BMR Calculator
Every calorie plan starts with a baseline, and Basal Metabolic Rate is that baseline: the energy your body would burn in a full day of doing absolutely nothing, just keeping you alive. This calculator estimates it with the Mifflin-St Jeor equation, the formula most dietitians and researchers reach for because it has held up better than older alternatives against measured metabolic rates. Add your activity level and you get TDEE, total daily energy expenditure, the estimate of what you actually burn on a normal day.
The activity level you pick does most of the work in the final number, so honesty here matters more than precision anywhere else. “Lightly active” means a few real workouts a week, not a job where you occasionally stand up. Most desk workers who exercise two or three times a week land in lightly or moderately active; people regularly overestimate, which is how TDEE calculators end up promising more food than reality allows. When in doubt, pick the lower of the two levels you're torn between and adjust after a few weeks of real-world results.
Treat the output as a starting hypothesis, not a prescription. Individual metabolism varies with muscle mass, hormones, medications, and history of dieting, and no equation knows your body. The practical move is to use the TDEE as your initial target, eat and track consistently for two to three weeks, and let the scale and the mirror correct the estimate. This tool is for informational purposes and is not medical advice, for a real plan, talk to a registered dietitian.
How to use BMR Calculator
- Enter your age, sex, height and weight.
- Pick the activity level closest to your routine.
- Read your BMR and TDEE estimates.
Why use this tool?
- Uses the widely trusted Mifflin-St Jeor equation
- Five activity levels for a tailored TDEE
- Free with no signup
Tips for best results
- Be honest about activity: most desk workers with 2–3 workouts a week are “lightly active,” not “moderately active.”
- Recalculate after meaningful weight change, BMR drops as you get lighter, so a stale number quietly overfeeds you.
- Use the TDEE as a starting target for 2–3 weeks, then adjust based on actual weight trend rather than defending the estimate.
- Don't add exercise calories on top of an active-level TDEE; the activity multiplier already accounts for your workouts.
- The equation is least accurate at extremes of leanness or obesity, treat results there as especially rough.