BMR Calculator

What BMR tells you

Basal Metabolic Rate (BMR) is an estimate of the number of calories your body requires at complete rest to maintain basic physiological functions: breathing, circulation, cell production and temperature regulation. It forms the baseline of daily energy needs. Total daily energy expenditure (TDEE) is calculated by applying an activity multiplier to BMR.

This calculator uses the Mifflin-St Jeor equation, a commonly used method shown to be reasonably accurate across adult populations. It requires inputs for sex, age, weight and height. Use the resulting number to guide nutrition decisions, but remember it is an estimate. Individual metabolic rates vary due to genetics, lean mass, hormones and recent calorie history.

Using your BMR

After calculating BMR, multiply by your typical activity level to estimate maintenance calories. For example, a sedentary person might multiply by ~1.2 while a very active person may use 1.6 or higher. If your goal is weight loss or gain, adjust calories gradually and monitor progress rather than making large changes at once.

Health considerations

BMR does not capture all aspects of health and should be combined with assessment of diet quality, physical activity, sleep and medical conditions. Before making significant dietary changes, particularly if you have medical conditions, consult with a healthcare professional or registered dietitian for personalised guidance.