Find your basal metabolic rate, the calories your body burns at complete rest, using the Mifflin-St Jeor equation.
Basal Metabolic Rate (BMR) is the number of calories your body needs to accomplish its most basic (basal) life-sustaining functions.
What BMR measures:
Activity Levels:
This calculator uses the Mifflin-St Jeor Equation, which is considered more accurate than the Harris-Benedict Equation for most people.
Type your age, sex, weight, and height. We use the Mifflin-St Jeor equation, which is the most accurate BMR formula for most non-athletic adults.
BMR is the calories your body burns at complete rest to maintain breathing, circulation, cell production, and brain function. It excludes any activity.
BMR alone underestimates total calorie needs. Multiply by 1.2 (sedentary) to 1.9 (very active) to get TDEE, your true daily calorie burn.
For related calculations, try our TDEE calculator.
Cross-checked against authoritative formulas (IRS, NIST, ACM) and updated for 2025/2026 tax years and rates.
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Estimates only. Calculator results are for educational and planning purposes — not professional advice. For binding decisions on taxes, investments, health, or legal matters, consult a qualified professional.
FAQ
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A BMR calculator is a free tool that estimates your basal metabolic rate, the calories your body burns at complete rest to maintain vital functions. Our BMR calculator uses the Mifflin-St Jeor equation, which is considered the most accurate for most adults. The BMR calculator results are the baseline for any TDEE or weight management calculation.
How it works
Our bmr calculator lets you find the number of calories your body burns at complete rest using the Mifflin-St Jeor equation, in three steps.
Type your age in years, pick your biological sex, and enter height and weight. The calculator uses these four values in the BMR formula.
Choose Mifflin-St Jeor (default and most accurate) or the older Harris-Benedict equation if you prefer a specific standard.
The result is the number of calories your body needs to maintain basic functions at rest. To estimate your total daily burn, multiply this by an activity factor.
Discover a holistic approach to health and fitness planning using BMR, TDEE, and body composition calculators.
Understand the differences between BMI and body fat percentage, and how BMR fits into your health picture.