BMR Calculator

What is BMR?

Basal Metabolic Rate (BMR) is the minimum number of calories your body needs to perform its most basic functions while completely at rest. These functions include breathing, circulating blood, regulating body temperature, growing and repairing cells, and maintaining brain and nervous system activity. BMR accounts for roughly 60–70% of total daily energy expenditure for most people, which makes it the single largest component of how many calories you burn each day.

Several factors influence BMR — including age, gender, body size, and muscle mass. People with more lean muscle generally have a higher BMR because muscle tissue is metabolically more active than fat. BMR also naturally decreases with age. This calculator uses the Mifflin-St Jeor equation, widely considered the most accurate formula for estimating BMR in healthy adults and the standard used by registered dietitians and fitness professionals today.

How to Use This Calculator

• Select your preferred unit system — Metric (kg and cm) or Imperial (lbs, feet, and inches).
• Choose your gender — male and female formulas differ by a fixed constant.
• Enter your age in years.
• Enter your weight and height in the input fields.
• Your BMR value in kcal/day will appear instantly in the results panel.

Example

A 30-year-old male weighing 70 kg and standing 175 cm tall uses the male formula: BMR = 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 700 + 1093.75 − 150 + 5 = 1,648.75 kcal/day, which rounds to 1,649 kcal/day. This means his body burns about 1,649 calories per day even if he stays in bed all day doing nothing. Any physical activity on top of this adds to his total daily energy expenditure.

BMR vs TDEE

BMR is the calories burned at complete rest, while TDEE (Total Daily Energy Expenditure) is the total calories you burn in a day including activity — walking, working, exercise, and even digestion. TDEE is calculated by multiplying BMR by an activity factor (1.2 for sedentary, up to 1.9 for very active). To plan meals or track a calorie deficit/surplus, TDEE is the number you actually want. Use the TDEE Calculator to estimate your full daily calorie burn.