BMR Calculator
Your Basal Metabolic Rate (BMR) is the energy your body needs just to keep you alive — breathing, circulation and keeping warm. It is the starting point for any diet or weight plan.
These health tools are still being tested and are updated regularly to give you a better experience. Results are estimates for information only — please confirm important results with a doctor. Read the medical disclaimer
BMR Calculator
Next steps
- TDEE CalculatorWork out your Total Daily Energy Expenditure — all the calories you burn in a typical day.
- Daily Calorie CalculatorFind how many calories to eat each day to lose, keep or gain weight at a healthy pace.
- Lean Body Mass CalculatorEstimate how much of your body weight is muscle, bone, organs and water — everything except fat.
- Signs of Dehydration and How to Prevent Water Deficiency in the BodyHealth guide
About the BMR Calculator
BMR usually makes up 60–70% of the calories you burn in a day. It depends mainly on your weight, height, age and sex. Knowing it helps you set a realistic calorie target rather than guessing.
How to use the BMR Calculator
- Select your sex and enter your age (18 or over).
- Enter your height and weight in metric or US units.
- Keep the Mifflin–St Jeor equation (most accurate for most adults), or choose Katch–McArdle if you know your body fat %.
- Press Calculate to see your BMR and compare the equations.
Formula explained
Three equations are available. Mifflin–St Jeor (default, most accurate for most adults):
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Harris–Benedict (revised 1984): men 88.362 + 13.397W + 4.799H − 5.677A; women 447.593 + 9.247W + 3.098H − 4.330A.
Katch–McArdle: BMR = 370 + 21.6 × lean body mass (kg), using your body fat %.
The result is in kilocalories (kcal) per day.
Worked example: BMR
A 35-year-old woman, 158 cm and 62 kg: 10 × 62 + 6.25 × 158 − 5 × 35 − 161 = 1,272 kcal/day.
On a sedentary day she would burn about 1,272 × 1.2 ≈ 1,526 kcal in total.
Important limitations
- Equations estimate an average; an individual’s BMR can be 10% higher or lower.
- Not valid for children, pregnancy, or during illness, fever or recovery from surgery.
- Thyroid disorders and some medicines change BMR.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest. TDEE (Total Daily Energy Expenditure) adds everything else — walking, work, exercise and digesting food. TDEE is the number to use when planning how much to eat.
Can I increase my BMR?
Building muscle through strength training raises BMR slightly, because muscle uses more energy than fat. Very low-calorie diets can lower it, which is one reason crash diets often stop working.
Which BMR equation is most accurate?
For most adults, Mifflin–St Jeor (1990) is the most accurate of the common equations, and dietitians use it widely. Katch–McArdle can be better for very lean or muscular people if body fat % is measured accurately.
Should I eat my BMR in calories?
No — that would be too little for most people. Your daily needs (TDEE) are your BMR plus the energy you use moving around, usually 20–90% more. Use the TDEE or Daily Calorie Calculator for eating targets.
Sources
- Mifflin MD, St Jeor ST et al. Am J Clin Nutr 1990;51:241-7.
- Roza AM, Shizgal HM. Am J Clin Nutr 1984;40:168-82 (revised Harris–Benedict).
Medical disclaimer: These tools give general information and estimates only. They are not a diagnosis and do not replace advice from a qualified doctor. Always talk to your doctor about your results, and seek urgent medical help in an emergency. In an emergency call 112. Medical disclaimer · Terms of use · Privacy policy
