BMR Calculator

Estimate your Basal Metabolic Rate — the calories your body burns at rest.

Age yrHeight cmWeight kg

—calories/day at rest (BMR)

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About the BMR Calculator

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to keep you alive — powering your heart, brain, breathing and other basics. It's the starting point for understanding your energy needs and for any calorie plan to lose, maintain or gain weight. Enter your age, sex, height and weight to estimate it in metric or imperial units.

How it works — the formula

This uses the Mifflin-St Jeor equation, the formula most dietitians consider the most accurate for the general population:

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Imperial entries are converted to kilograms and centimetres first. The result is calories per day burned at rest — before any activity is added.

Assumptions and behaviour

Uses Mifflin-St Jeor, published in 1990 and widely regarded as more accurate than the older Harris-Benedict equation for most people.
Requires age, sex, height and weight; the two sexes use slightly different constants.
BMR is the resting figure — to get total daily calories, multiply by an activity factor (the Calorie Needs Calculator does this).
Rounded to the nearest calorie.

Limitations

It's an estimate for the general population. BMR varies with body composition — more muscle raises it, more fat lowers it — and the formula uses only height and weight, so it can't account for that.
It's less accurate for athletes, the very muscular, the elderly, or people at extremes of height or weight, where a body-composition measurement would be better.
It uses the traditional two-category (male/female) constants the equation was derived with.
This is general information, not medical or dietary advice — consult a professional before making significant changes to your eating or exercise.

Privacy

The calculation runs entirely in your browser. Your details are never uploaded or stored.

Frequently asked questions

Is this BMR calculator free?

Yes — free, no sign-up, no limits, runs in your browser.

What is BMR?

Basal Metabolic Rate — the calories your body burns at complete rest to keep basic functions going. It's your baseline energy need before any activity.

Which formula does it use?

The Mifflin-St Jeor equation, widely regarded as the most accurate for the general population — more so than the older Harris-Benedict formula.

How do I get my total daily calorie needs?

Multiply BMR by an activity factor (from sedentary to very active). The Calorie Needs Calculator does this step for you.

How accurate is it?

It's a solid estimate for most people, but it uses only height and weight, so it can't account for body composition — it's less accurate for very muscular, elderly, or extreme cases.

Is my data uploaded?

No. Everything runs locally in your browser; nothing is sent or stored.

Is this medical advice?

No. It's general information. Consult a doctor or dietitian before making significant changes to your diet or exercise.

Written by Lakshay Kumar(TechLakshay)

A QA Automation Engineer by trade, Lakshay's real passion is untangling complex problems into simple, working solutions — which is exactly why FreeMyTask exists. On Instagram, he channels that same instinct into helping 26,000+ content creators with SEO education, motivation, and hands-on query solving.

Last updated: August 22, 2026