BMR Calculator
Your BMR is the number of calories your body burns just to keep you alive - before any activity. This calculates it using three different formulas so you can see how they compare.
How to use
- Pick your units for weight and height separately.
- Enter your age, weight, and height.
- If you know your body fat percentage, add it for the Katch-McArdle formula, which is more accurate for lean people.
- Hit Calculate to see your BMR across all three formulas.
Related tools:
Basal Metabolic Rate (BMR) is the number of calories your body needs to perform its most basic life-sustaining functions (breathing, circulation, cell production, and temperature regulation) while at complete rest. It accounts for roughly 60–75% of your total daily calorie expenditure. Knowing your BMR is the first step in calculating how many calories you need to eat to lose, maintain, or gain weight.
Our BMR calculator offers three formulas: Mifflin-St Jeor (most accurate for most people), Harris-Benedict (revised 1984 version), and Katch-McArdle (best when you know your body fat percentage). Multiply your BMR by an activity multiplier to get your TDEE, the total calories you burn in a day.
Frequently Asked Questions
What is a normal BMR for an adult?
For an average adult woman (30 years, 60 kg, 165 cm), BMR is approximately 1,400 calories/day. For an average adult man (30 years, 75 kg, 175 cm), it is approximately 1,750 calories/day. BMR decreases with age and increases with muscle mass.
Which BMR formula is most accurate?
The Mifflin-St Jeor equation is considered the most accurate for most people. The Katch-McArdle formula is more accurate if you know your body fat percentage, as it uses lean body mass rather than total weight.
Does BMR change with age?
Yes. BMR typically decreases by about 1–2% per decade after age 20, mainly due to the loss of muscle mass (sarcopenia). Regular strength training can slow this decline significantly.
Can I increase my BMR?
Yes. Building muscle through resistance training is the most effective way to increase BMR, as muscle tissue burns more calories at rest than fat tissue. Adequate protein intake and avoiding very low-calorie diets also help maintain BMR.