BMR Calculator
The BMR Calculator estimates your Basal Metabolic Rate (BMR), the number of calories your body burns at rest to maintain basic functions like breathing, circulation, and cell production. BMR represents the minimum energy your body needs to survive. Knowing your BMR helps you plan calorie intake for weight loss, maintenance, or gain. This calculator uses the Mifflin-St Jeor equation, which is considered the most accurate formula for most people.
Formula
Mifflin-St Jeor Equation: Men: BMR = 10W + 6.25H - 5A + 5 Women: BMR = 10W + 6.25H - 5A - 161 W = weight (kg), H = height (cm), A = age TDEE = BMR x activity factor: - Sedentary: 1.2 - Light: 1.375 - Moderate: 1.55 - Active: 1.725 - Very active: 1.9
Example
Male, 30 years, 75 kg, 178 cm: BMR = 10(75) + 6.25(178) - 5(30) + 5 BMR = 750 + 1112.5 - 150 + 5 BMR = 1717.5 calories/day With moderate activity: TDEE = 1717.5 x 1.55 = 2662 calories/day
How to Use
- Enter your gender, age, weight, and height
- The calculator uses the Mifflin-St Jeor equation
- Review your BMR (calories burned at rest)
- Select your activity level to see TDEE
- Use TDEE to plan your calorie intake
Frequently Asked Questions
What is BMR?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic life functions. It accounts for 60-70% of your daily calorie burn. BMR varies by age, gender, weight, height, and genetics.
What is the difference between BMR and TDEE?
BMR is calories burned at rest. TDEE (Total Daily Energy Expenditure) includes BMR plus calories burned from activity and digestion. TDEE = BMR x activity factor. Use TDEE for calorie planning, not BMR alone.
Which BMR formula is most accurate?
The Mifflin-St Jeor equation is considered the most accurate for most people. It was developed in 1990 and is more accurate than the older Harris-Benedict equation. The Katch-McArdle formula, which uses body fat percentage, is even more accurate but requires body fat measurement.
How many calories should I eat to lose weight?
To lose weight, eat fewer calories than your TDEE. A deficit of 500 calories/day leads to about 1 pound of weight loss per week. Never eat below your BMR without medical supervision, as this can slow metabolism and cause health issues.
Does BMR change with age?
Yes. BMR typically decreases by 1-2% per decade after age 20, primarily due to loss of muscle mass. Strength training can help maintain muscle and keep BMR higher as you age. Women's BMR also changes with hormonal fluctuations.