🔥 BMR Calculator

Estimate your basal metabolic rate — calories burned at rest.

About this tool

Estimates basal metabolic rate (BMR) — the number of calories your body burns at complete rest just to maintain basic functions like breathing, circulation, and cell repair — using the Mifflin-St Jeor equation, widely regarded as one of the more accurate general-purpose formulas.

BMR is a foundation figure, not a total daily calorie need — see the Calorie Calculator for an estimate that adds activity level on top of this.

Worked example

A 30-year-old male, 70 kg, 175 cm tall has an estimated BMR of about 1,674 calories per day — the energy his body would burn lying still for 24 hours.

How to use it

Choose metric or imperial units.
Select sex (the formula uses different constants for male and female bodies, based on typical differences in body composition).
Enter age, weight, and height.
Press Calculate BMR.

Tips

BMR alone isn't your total daily calorie needs — it doesn't include any activity. Use the Calorie Calculator to add an activity multiplier on top.
The Mifflin-St Jeor equation is generally considered more accurate than the older Harris-Benedict formula for most people.
Individual metabolism varies due to muscle mass, genetics, and health conditions — treat this as a solid estimate, not an exact measurement.

FAQ

What's the difference between BMR and calorie needs?

BMR is calories burned at complete rest; total daily calorie needs (sometimes called TDEE) add your activity level on top of BMR — use the Calorie Calculator for that fuller figure.

Why does the formula ask for sex?

The Mifflin-St Jeor equation uses different constants for male and female bodies to account for typical average differences in muscle mass and body composition, which affect resting metabolic rate.

Is this exact?

No — it's a well-validated estimate based on population averages. Actual BMR varies by individual factors like muscle mass and genetics that a formula based only on age, weight, height, and sex can't fully capture.

From the blog: getting the most out of this tool

BMR is the number underneath every calorie-counting app's daily target, even when the app doesn't show it directly — it's the resting baseline that activity level and goal adjustments get layered on top of.

We used Mifflin-St Jeor rather than the older Harris-Benedict formula because it's generally regarded as more accurate for a broader range of body types, based on how it was validated against measured data.