Calculate your Basal Metabolic Rate — the calories your body burns at rest — using the Mifflin-St Jeor and Harris-Benedict formulas with TDEE estimates.
Enter your figures and click Calculate to see your results.
Enter your gender, age, weight in kg and height in cm — the calculator shows BMR from both major formulas plus TDEE estimates.
Press the Calculate button. Results appear instantly using standard clinical and scientific formulas.
Results are displayed with all key values clearly labelled. Use the Copy button to grab your results or Download to save a text file. For health decisions, always consult a healthcare professional.
Basal Metabolic Rate (BMR) is the number of calories your body requires to maintain basic life functions at complete rest — breathing, circulation, temperature regulation, organ function and cell production. BMR typically accounts for 60–70% of total daily energy expenditure.
The Mifflin-St Jeor equation (1990) is the most accurate for most modern adults and is recommended by most dietitians. The Harris-Benedict equation (1919, revised 1984) is also widely used. The two typically differ by 5–10%. For overweight individuals, the Katch-McArdle formula (using lean body mass) can be more precise.
Multiply BMR by your Physical Activity Level (PAL) to get TDEE. To lose weight: eat 300–500 kcal below TDEE for gradual loss (~0.5 kg/week). Never eat below your BMR for extended periods — this causes muscle loss and metabolic adaptation. The best approach is a moderate deficit with adequate protein and strength training.
Yes — BMR declines roughly 1–2% per decade after age 30, partly due to natural muscle loss (sarcopenia). This is why maintaining muscle mass through strength training is important as you age. BMR is also temporarily elevated during illness/fever and reduced during prolonged calorie restriction.
BMR is higher with greater muscle mass (muscle is metabolically active), younger age, taller height, being male (higher average muscle mass), pregnancy, hyperthyroidism and cold environments. Building muscle through resistance training is the most effective long-term strategy to raise BMR and support weight management.
