Basal Metabolic Rate Calculator
The Basal Metabolic Rate Calculator estimates the calories your body burns at rest each day from your sex, age, weight in kilograms, and height in centimeters using the Mifflin-St Jeor equation.
What this calculator does
The Basal Metabolic Rate Calculator estimates your result instantly from the values you enter, using standard health & fitness formulas. The Basal Metabolic Rate Calculator estimates the calories your body burns at rest each day from your sex, age, weight in kilograms, and height in centimeters using the Mifflin-St Jeor equation. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate rather than a certified or official figure.
Result
This tool is for general informational purposes only and is not a substitute for professional medical advice.
About Basal Metabolic Rate Calculator
Basal metabolic rate is the energy your body uses at complete rest. This calculator applies the Mifflin-St Jeor equation, a standard formula that combines weight, height, age, and sex.
The result estimates daily calories at rest; the tool notes that multiplying by an activity factor of 1.2 to 1.9 approximates total daily energy expenditure.
Formula & Mathematical Calculation
bmr = (10 × weight) + (6.25 × height) - (5 × age) + (sex === 'male' ? 5 : -161)
Derived directly from the verified calculation function in the tool engine.
Calculation Example
For a male aged 30, weighing 70 kg at 175 cm: BMR = (10 × 70) + (6.25 × 175) − (5 × 30) + 5.
That is 700 + 1093.75 − 150 + 5 = 1648.75, rounded to 1,649 cal/day.
Key Benefits
- Uses the Mifflin-St Jeor equation, a widely referenced BMR formula.
- Accounts for sex with a +5 term for males and -161 for females.
- Takes metric inputs of weight in kilograms and height in centimeters.
- Provides the activity-factor range (1.2 to 1.9) for estimating total daily expenditure.
How to Use this Calculator
-
Select sex
Choose Male or Female. -
Enter age
Type your age in years. -
Enter weight and height
Enter your weight in kilograms and height in centimeters. -
Calculate and read
Select Calculate and read the Basal Metabolic Rate in calories per day.
Assumptions & Limitations
What the calculation assumes
- Every value you enter is treated as an exact, known amount.
- Any rate or interval you enter is assumed to hold for the whole period unless the form asks for it separately.
- Results use standard published formulas and account only for the values entered above.
- Rounding is applied for display; the underlying calculation uses your full precision.
- Results are returned in the same units you enter, unless the tool states the output unit.
What it does not cover
- Basal Metabolic Rate Calculator produces a calculated result for reference and learning, not a certified or official measurement.
- Real-world outcomes differ when tolerances, rounding rules or local standards apply.
- Definitions and standards vary by region and change over time; verify the convention that applies to your case.
- Figures are only as accurate as the inputs you supply — check them before acting on the result.
- For work where the result carries real consequences, confirm it against an authoritative source.
Frequently Asked Questions
Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.