What is BMR?
Basal metabolic rate (BMR) is the number of calories your body needs at complete rest to keep you alive: breathing, circulation, cell repair and temperature control. It typically accounts for 60–70% of the calories you burn in a day.
The two equations
- Mifflin-St Jeor (1990) is considered one of the most accurate for healthy adults. Men: 10 × kg + 6.25 × cm − 5 × age + 5. Women: the same with −161.
- Revised Harris-Benedict (1984) is an older formula that often gives slightly higher values.
From BMR to daily calories
Multiply your BMR by an activity factor from 1.2 (sedentary) to 1.9 (very active) to estimate your total daily needs. Our Calorie Calculator does this for you.
What affects BMR?
Muscle mass, age, sex, body size, genetics and hormones all play a part. Building muscle through strength training raises your BMR, while it tends to decline gradually with age.
Frequently asked questions
Which equation should I trust?
Mifflin-St Jeor is generally preferred. The two results are usually within about 5% of each other.
Does BMR include exercise?
No. It is the energy used at rest only.
Can I eat BMR calories to lose weight?
Eating well below your needs can be harmful. Consult a professional before making large changes.