Lifestyle
Food & Nutrition
FitnessCalculate your basal metabolic rate, the calories your body burns at rest.
This tool is for general information only and is not medical advice. Talk to a healthcare professional about results that concern you.
What Is BMR?
Your basal metabolic rate is the number of calories your body burns at complete rest, just keeping your heart beating, lungs breathing, brain working, and cells repairing. For most people it accounts for 60 to 70 percent of all the calories they burn in a day, far more than exercise does.
This calculator uses the Mifflin-St Jeor equation, the formula the American Dietetic Association found most accurate for estimating resting metabolism. For comparison it also shows the older Harris-Benedict estimate.
The Mifflin-St Jeor Formula
- Men: (10 x weight in kg) + (6.25 x height in cm) – (5 x age) + 5
- Women: (10 x weight in kg) + (6.25 x height in cm) – (5 x age) – 161
BMR on its own is not a calorie target. Nobody spends the day lying motionless. To turn BMR into the calories you actually need, multiply it by an activity factor between 1.2 (sedentary) and 1.9 (very hard training). The results table above does this for every level, and our calorie calculator builds weight loss and weight gain targets on top of it.
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest. TDEE is your total burn for the day, which adds digestion, walking around, and workouts on top of BMR. TDEE is the number to use for setting calorie targets.
Can I increase my BMR?
Yes, mainly by building muscle. Each kilogram of muscle burns more calories at rest than a kilogram of fat. Strength training two to three times a week plus adequate protein is the most reliable way to nudge your BMR upward.
Is it bad to eat below my BMR?
It is not automatically dangerous, but it is usually unnecessary and hard to sustain. Very low intakes make it difficult to get enough protein and micronutrients, and they accelerate muscle loss. A moderate deficit below TDEE works better long term.
Why does BMR drop with age?
Mostly because people lose muscle as they age, not because metabolism inherently collapses. Research shows metabolism stays fairly stable from age 20 to 60 when adjusted for body composition. Keeping your muscle keeps your BMR.
Sources
- A new predictive equation for resting energy expenditure in healthy individuals · The American Journal of Clinical Nutrition (Mifflin et al., 1990)
- The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass · The American Journal of Clinical Nutrition (Roza & Shizgal, 1984)
- Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review · Journal of the American Dietetic Association (Frankenfield et al., 2005)
- A Biometric Study of Human Basal Metabolism · PMC (PNAS, Harris & Benedict, 1918)
This calculator is for general information only and is not a substitute for professional medical advice.