Skip to main content
Professor Peptides
FREE Calculator

BMR Calculator

Calculate your basal metabolic rate with the Mifflin–St Jeor equation, plus your total daily energy expenditure across every activity level.

BMR Calculator

Enter your details to estimate your resting metabolism

Your Results

Complete the form to see your BMR

Basal metabolic rate and TDEE across activity levels

Understanding Basal Metabolic Rate
What is BMR?

Basal metabolic rate is the energy your body burns at complete rest — the calories required to keep your heart, lungs, brain, and cells functioning. It typically accounts for 60–75% of total daily burn.

The Mifflin–St Jeor Equation

This calculator uses the Mifflin–St Jeor equation, which research has shown to be one of the most accurate BMR formulas for most adults. It factors in weight, height, age, and sex.

Why it matters: knowing your BMR is the first step toward setting a calorie target that supports your goals without guesswork.
From BMR to TDEE
Total Daily Energy Expenditure

Your TDEE multiplies BMR by an activity factor that estimates how much additional energy you burn through movement, exercise, and daily life.

  • Sedentary: BMR × 1.2 — little or no exercise
  • Lightly active: BMR × 1.375 — exercise 1–3 days/week
  • Moderately active: BMR × 1.55 — exercise 3–5 days/week
  • Very active: BMR × 1.725 — exercise 6–7 days/week
  • Extra active: BMR × 1.9 — athlete or physical job
Tip: your maintenance calories sit at your TDEE. Eat below it to lose fat, at it to maintain, and above it to build muscle.

Important Note

BMR estimates are a starting point and vary with muscle mass, genetics, and metabolic health. Track your weight and energy for 2–3 weeks and adjust your intake based on actual results. This calculator is for educational purposes only.