BMR Calculator

Estimate your basal metabolic rate (BMR), the calories your body uses at rest, with the Mifflin-St Jeor equation. You'll also see roughly how many calories you burn per day at each activity level.

An estimate for healthy adults

These formulas don't apply to people under 18, during pregnancy or breastfeeding, or with medical conditions that affect metabolism or weight. Talk to a doctor or registered dietitian before changing how you eat.

Basal metabolic rate (kcal/day)

1,370

Little or no exercise: 1,643 kcal/day
Light exercise 1–3 days a week: 1,883 kcal/day
Moderate exercise 3–5 days a week: 2,123 kcal/day
Hard exercise 6–7 days a week: 2,362 kcal/day
Very hard exercise or physical job: 2,602 kcal/day

Results are estimates for information only and do not constitute financial, medical, or legal advice.

How it works

The calculator uses the Mifflin-St Jeor equation, published in 1990 from measurements of 498 healthy adults, and later recommended by the Academy of Nutrition and Dietetics for estimating resting energy needs. It depends on your weight, height, age, and sex.

The formula

BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 (men) or − 161 (women)

Worked example

A 30-year-old woman who weighs 65 kg (143 lb) and is 165 cm (5 ft 5 in) tall.

10 × 65 + 6.25 × 165 − 5 × 30 − 161.
650 + 1,031.25 − 150 − 161 = about 1,370 calories a day at rest.

Sources

Mifflin MD, St Jeor ST, et al.A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990.

Frequently asked questions

What is BMR?

Basal metabolic rate is the energy your body uses at rest to keep you alive: breathing, circulation, temperature, and cell repair. It's usually the largest part of the calories you burn each day.

How accurate is the Mifflin-St Jeor equation?

It's one of the most widely used equations for healthy adults, and studies have found it estimates resting metabolism within about 10% for most people. Your real BMR can differ, especially with a lot of muscle, a medical condition, or certain medications. Only a lab test can measure it directly.

Should I eat only my BMR in calories?

No. BMR is what you burn at complete rest. Everyday movement and exercise add to it, so eating only your BMR is usually too little. A doctor or registered dietitian can help you find the right amount for you.