BMI, BMR and TDEE Calculators

BMR Formulas

Mifflin-St Jeor: Uses age, sex, height, and weight to estimate basal metabolic rate. It is a practical default for many adults because it is widely used and simple to compare over time.

Harris-Benedict: Another long-running BMR calculator formula using age, sex, height, and weight. Use it as a comparison point rather than a guaranteed calorie target.

McArdle-Katch: Estimates BMR from lean body mass, so it requires a body fat percentage estimate. It can be useful for lifters who already track body composition, but the output depends on how accurate that body fat input is.

TDEE and Calorie Targets

Total daily energy expenditure multiplies BMR by an activity level to estimate maintenance calories. The weight loss and weight gain targets shown here use a simple 500 calorie daily adjustment as a starting point.

Real calorie needs can shift with training volume, step count, sleep, stress, food tracking accuracy, and body-weight trend. Track results for a few weeks, then adjust gradually.

BMI Categories

Adult BMI categories commonly use under 18.5 for underweight, 18.5 to 24.9 for healthy weight, 25.0 to 29.9 for overweight, and 30.0 or higher for obesity.

BMI is a screening measurement based on height and weight. It does not directly measure body fat, muscle mass, bone density, or fat distribution, so it should be interpreted with context.