How BMR is calculated
Basal Metabolic Rate is the energy your body uses at rest for breathing, circulation and cell production. We use the Mifflin-St Jeor equation by default. If you enter your body fat percentage, we switch to the Katch-McArdle formula, which is based on lean body mass and is more accurate for lean or muscular people.
How to use it
Enter your gender, age, weight and height. Optionally add your body fat percentage to use the more precise Katch-McArdle formula. Your BMR is the minimum calories you need; multiply it by an activity factor (see the TDEE calculator) to get your daily needs.
Frequently asked questions
- What is the difference between BMR and TDEE?
- BMR is calories burned at rest. TDEE is BMR plus the calories you burn through daily activity and exercise.
- Should I eat below my BMR?
- Generally no. Eating below your BMR for long periods can be unsafe; aim your deficit between your BMR and TDEE.
- When should I use Katch-McArdle?
- Use it when you know your body fat percentage, especially if you are very lean or muscular, as it accounts for lean mass.
- Why did my BMR change?
- BMR drops with age and weight loss and rises with more lean muscle. Recalculate as your body changes.