Our free BMR calculator — Basal Metabolic Rate calculator — estimates the number of calories your body burns at complete rest to sustain basic life functions. Your BMR includes the energy required for breathing, blood circulation, cell production, and maintaining body temperature. It represents the minimum calories you need each day, even if you did nothing at all.
This BMR calculator offers three different formulas — Mifflin-St Jeor (recommended for most people), Harris-Benedict (Revised), and Katch-McArdle. Understanding your BMR is the first step in calculating your total daily calorie needs and designing an effective nutrition plan.
🫀 BMR Calculator
🫀 BMR Result
BMR is an estimate of calories burned at rest. Actual metabolic rates vary. Consult a registered dietitian for personalized guidance.
How to Use the BMR Calculator
Follow these steps to calculate your BMR:
- Enter your age and select your sex.
- Select your preferred unit system and enter your height and weight.
- Select your preferred formula — Mifflin-St Jeor is recommended for most people.
- Click Calculate BMR to see your BMR and estimated TDEE at different activity levels.
When Should You Use a BMR Calculator?
Use the BMR calculator as the foundation for any nutrition or weight management plan. Once you know your BMR, multiply it by your activity factor to get your Total Daily Energy Expenditure (TDEE). Then adjust your calorie intake up or down based on your goal — weight loss, maintenance, or muscle gain.
Furthermore, recalculate your BMR whenever your weight changes significantly, as BMR decreases with weight loss and increases with muscle gain. Additionally, your BMR naturally decreases as you age, which is why maintaining muscle mass through strength training becomes increasingly important over time.
How to Use Your BMR for Weight Management
Your BMR is a crucial number for effective weight management. Here is how to use it:
- For weight loss — Eat 500 calories below your TDEE to lose approximately 1 pound per week. Never eat below your BMR without medical supervision.
- For weight maintenance — Eat at your TDEE level to maintain your current weight.
- For muscle gain — Eat 250–500 calories above your TDEE and prioritize protein intake to support muscle growth.
- Build muscle to raise your BMR — Muscle tissue burns more calories at rest than fat tissue. Strength training is one of the best long-term strategies for increasing BMR.
Frequently Asked Questions About the BMR Calculator
Which BMR formula is the most accurate?
The Mifflin-St Jeor equation is currently considered the most accurate for most healthy adults. The Katch-McArdle formula is more accurate if you know your body fat percentage, as it accounts for lean body mass.
Does BMR decrease with age?
Yes. BMR tends to decrease by approximately 1–2% per decade after age 20, primarily due to the loss of muscle mass. This is why maintaining muscle through strength training becomes increasingly important with age.
Related Calculators
Furthermore, you might find these related tools useful: Calorie Calculator — BMI Calculator — Body Fat Calculator — Ideal Weight Calculator
Disclaimer: BMR estimates are based on mathematical formulas and individual results may vary. Consult a registered dietitian or physician before significantly changing your diet.