BMR Calculator
Estimate basal metabolic rate with the Mifflin-St Jeor formula locally in your browser.
Estimated calories your body uses at rest for basic functions.
Use this as the starting point for estimating TDEE and daily calorie targets.
Mifflin-St Jeor is commonly used as a starting estimate for adults.
BMR is an estimate. Real metabolism can vary with muscle mass, health status, sleep, hormones, and other factors.
About this tool
Estimate basal metabolic rate with the Mifflin-St Jeor formula locally in your browser.
Your body measurements are calculated locally in your browser and are not uploaded to a server.
BMR is a formula estimate and does not replace medical, nutrition, or metabolic testing. Health conditions, medication, pregnancy, age, muscle mass, and training status can change real energy needs.
How to use it
- Choose sex.
- Enter age, height, and weight.
- Review estimated BMR and formula notes.
Common use cases
- Estimate resting calorie needs
- Use BMR as the base for TDEE
- Start daily calorie planning with a formula estimate
How BMR Is Estimated
This calculator uses the Mifflin-St Jeor equation. It estimates resting energy needs from sex, age, height, and weight, then can be used as the base for TDEE.
| Input | Why it matters | Reminder |
|---|---|---|
| Sex | The formula uses different constants for male and female settings | This is a formula field, not a complete picture of physiology. |
| Age | Estimated resting needs usually decrease with age | Real metabolism varies by person. |
| Height and weight | Used to estimate body size and resting energy | Muscle mass is not directly measured. |
FAQ
Which formula is used?
This calculator uses the Mifflin-St Jeor equation, a common adult resting energy estimate.
Is BMR the same as daily calories?
No. BMR estimates resting needs. TDEE adds activity on top of BMR.
Are my inputs uploaded?
No. The calculation runs locally in your browser.