BMR Calculator

A BMR calculator estimates your Basal Metabolic Rate — the calories your body burns at complete rest just to keep you alive, running your heart, brain, lungs, and everything else. It uses the Mifflin-St Jeor equation, which clinicians generally prefer for accuracy. BMR is the floor your daily needs sit on; add movement and exercise on top to get your full daily requirement. It runs in your browser.

How to use it

1. Enter your weight, height, age, and sex.
2. Your BMR appears instantly, in calories per day.
3. To find your full daily need, use the calorie calculator, which adds your activity level.

Examples

• Male, 70 kg, 175 cm, 25 years → 1,673.75 calories a day at rest.
• Female, same measurements → 1,507.75 calories a day.

Frequently asked questions

What is BMR and why does it matter?

BMR is what you'd burn lying still all day — the energy for breathing, circulation, and cell repair. It typically accounts for 60–70% of the calories you use, which is why it's the foundation of any nutrition plan.

Which BMR equation does this use?

The Mifflin-St Jeor equation, published in 1990. It's generally considered more accurate for modern populations than the older Harris-Benedict formula and is widely used in clinical practice.

BMR vs TDEE — what is the difference?

BMR is your resting burn. TDEE — Total Daily Energy Expenditure — is BMR multiplied by an activity factor, so it includes walking, work, and exercise. TDEE is the number to eat around; BMR is the baseline it's built from.

Can I eat below my BMR to lose weight?

It's generally not advised. Eating below BMR for long periods can cost you muscle, energy, and nutrients, and it's difficult to sustain. A moderate deficit from your TDEE is safer and works better. Speak to a doctor or dietitian before any aggressive restriction.