BMR calculator
BMR Calculator
Your BMR (basal metabolic rate) is the calories your body burns at complete rest. Enter your details to calculate it with the Mifflin-St Jeor equation — the foundation of every calorie target.
Why BMR matters
BMR is 60-70% of the calories most people burn in a day — the baseline cost of simply being alive. It's the starting point for your TDEE (BMR × activity) and therefore for how many calories you should eat. Knowing it helps you understand why crash diets backfire: eat far below BMR and your body fights back.
The Mifflin-St Jeor equation
Published in 1990, Mifflin-St Jeor replaced the older Harris-Benedict formula as the clinical standard because it better predicts resting energy expenditure across modern populations:
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
From BMR to a real plan
BMR alone doesn't tell you what to eat — multiply it by your activity to get yourmaintenance calories, then set a goal. To actually stay on target, the MyPlate app tracks every meal by photo or barcode, free on iOS and Android.
Frequently asked questions
What is BMR (basal metabolic rate)?
Your BMR is the number of calories your body burns at complete rest to keep you alive — breathing, circulation, cell production, and organ function. It typically accounts for 60-70% of the calories you burn each day, before any movement.
How is BMR calculated?
This calculator uses the Mifflin-St Jeor equation: for men, BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5; for women, the same minus 161 instead of plus 5. It is the formula dietitians use today because it predicts resting metabolism more accurately than the older Harris-Benedict equation.
What is the difference between BMR and TDEE?
BMR is calories burned at rest; TDEE is your total daily burn including movement and exercise (TDEE = BMR × activity factor). You never eat at just your BMR — your maintenance level is your TDEE. Use the TDEE calculator for that.
Can I eat at my BMR to lose weight?
It is not recommended. Eating at or below BMR for long periods can be too aggressive, sap energy, and reduce muscle mass. Base weight loss on a moderate deficit below your TDEE instead — and never go below 1,200 (women) / 1,500 (men) calories without medical supervision.
What lowers or raises BMR?
BMR rises with more muscle mass, greater height and weight, and younger age, and falls with age and muscle loss. Strength training and adequate protein help preserve muscle and keep BMR higher, which is why they matter during weight loss.