BMR Calculator
Find your Basal Metabolic Rate — the calories your body burns at complete rest.
About the BMR Calculator
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions — breathing, circulation, cell production, and temperature regulation — while completely at rest. It is the foundation of every calorie-based nutrition plan.
The Mifflin-St Jeor Equation
This tool uses the Mifflin-St Jeor equation, considered the most accurate for most people by major dietetic associations:
Male: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Female: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
BMR vs. TDEE
BMR is your resting calorie burn. Your Total Daily Energy Expenditure (TDEE) is BMR multiplied by an activity factor:
Sedentary (little/no exercise): BMR × 1.2 | Lightly active (1-3 days/week): BMR × 1.375 | Moderately active (3-5 days/week): BMR × 1.55 | Very active (6-7 days/week): BMR × 1.725 | Extremely active (physical job or twice daily training): BMR × 1.9
Why BMR Matters for Weight Management
To lose weight, consume fewer calories than your TDEE. A deficit of 500 calories per day leads to roughly 0.5 kg (1 lb) of fat loss per week. Never eat below your BMR for extended periods — your body will down-regulate metabolism and break down muscle tissue for energy.
Factors That Affect BMR
Muscle mass: Muscle burns more calories at rest than fat does. Strength training raises BMR over time. Age: BMR declines roughly 2% per decade after age 30 due to muscle loss. Hormones: Thyroid disorders can significantly raise or lower BMR. Body composition: Two people of the same weight can have BMRs differing by 20% if their fat-to-muscle ratio differs.