By ToolzHive
About this tool
Your basal metabolic rate (BMR) is the number of calories your body burns at complete rest just to keep you alive: breathing, circulating blood and keeping warm. This calculator uses the Mifflin–St Jeor equation, which research has found to be the most accurate everyday formula, and also offers the revised Harris–Benedict and Katch–McArdle equations. It then multiplies your BMR by five activity levels to estimate the calories you burn in a normal day (your TDEE).
How to use BMR Calculator
- Choose metric or imperial units, then enter your sex, age, height and weight.
- Pick a formula. Keep Mifflin–St Jeor unless you know your body fat percentage, in which case Katch–McArdle can be more accurate.
- Read your BMR and the table of daily calories for each activity level. Use the row that matches your week.
Worked example
A 30-year-old man who is 175 cm tall and weighs 70 kg has a BMR of about 1,649 kcal with Mifflin–St Jeor: 10 × 70 + 6.25 × 175 − 5 × 30 + 5. If he exercises 3–5 days a week, multiply by 1.55 to get about 2,556 kcal a day.
What is the difference between BMR and TDEE?
BMR is the energy you use at complete rest. TDEE (total daily energy expenditure) adds everything else: walking, exercise, work and digesting food. TDEE is the number to use when planning how much to eat.
Which BMR formula is most accurate?
For most adults, Mifflin–St Jeor is the most accurate of the common equations, usually within about 10% of measured values. Katch–McArdle can be better for lean or very muscular people because it uses lean body mass.
Why is my BMR lower than I expected?
BMR falls with age and with lower muscle mass, and women usually have lower BMRs than men of the same size. Remember it is only your resting burn; your real daily needs are higher.
Put this guide into practice
- BMR Calculator — Calculate your basal metabolic rate with Mifflin–St Jeor, Harris–Benedict or Katch–McArdle.