Nutrition planning
Estimate a baseline calorie number before adjusting for daily activity levels.
Calculator tools
BMR Calculator
Estimate daily baseline energy needs with the Mifflin-St Jeor equation.
How to use
- 1
Enter age, sex, height, and weight.
- 2
Calculate BMR.
- 3
Use the result as an informational estimate.
Quick answer
BMR Calculator estimates basal metabolic rate—the calories your body likely burns at rest—from age, sex, height, and weight using the Mifflin-St Jeor equation. It is an informational starting point, not medical or dietary advice.
Key features
- Calculates BMR using the widely used Mifflin-St Jeor formula.
- Accepts structured inputs for age, sex, height, and weight.
- Runs locally in the browser without storing personal health values on a server.
- Provides a clear baseline number before activity multipliers or diet planning.
- Supports metric and common unit inputs depending on the form layout.
- Includes health disclaimers because individual metabolism varies significantly.
About this tool
Basal metabolic rate estimates the energy your body may use at rest to maintain basic functions such as breathing, circulation, and cell repair. Fitness apps, nutrition plans, and calorie targets often start with BMR before applying activity multipliers. This calculator uses the Mifflin-St Jeor equation, one of the commonly referenced formulas in consumer health tools. Results can differ from lab measurements, medical assessments, or wearable-device estimates because real metabolism depends on muscle mass, health conditions, medications, sleep, and genetics. Treat the output as a planning number rather than a prescription. Because calculations run locally in your browser, height, weight, and age inputs stay on your device during normal use.
Common scenarios
Fitness app cross-check
Compare app-generated BMR values with an independent browser calculation.
Wellness tracking
Track how baseline energy estimates change as weight or age inputs change over time.
Educational use
Demonstrate how height, weight, age, and sex affect resting energy estimates.
FAQ
Which formula is used?
It uses the Mifflin-St Jeor equation.
Is this health advice?
No. It is an informational estimate only and does not replace professional medical or dietary guidance.
Does BMR include exercise?
No. BMR estimates resting energy only. Activity calories require a separate multiplier or TDEE calculation.
Are my inputs uploaded?
No. BMR calculation runs locally in your browser.
Why can results differ from my fitness tracker?
Devices and apps may use different formulas, activity assumptions, or personal calibration data.
Should athletes rely on BMR alone?
No. Athletes with higher muscle mass may need personalized nutrition guidance beyond a generic formula.