What is BMR (Basal Metabolic Rate)?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest over 24 hours. It represents the energy required to maintain vital functions such as breathing, heartbeat, body temperature regulation, and organ function. BMR accounts for approximately 60–75% of your total daily energy expenditure.
How to calculate BMR?
This calculator uses the Mifflin-St Jeor formula — the most accurate modern method for estimating BMR:
- Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
- Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
Enter your weight, height, age and sex — the result updates automatically.
What is the BMR formula?
The Mifflin-St Jeor formula was developed in 1990 and is considered more accurate than the older Harris-Benedict formula. The key variables are body weight, height, age, and sex. Men typically have a higher BMR than women due to a greater proportion of lean muscle mass.
What are some BMR examples?
Example calculations using the Mifflin-St Jeor formula:
- Male, age 30, 80 kg, 180 cm: BMR ≈ 1,780 kcal/day (≈ 74 kcal burned per hour of sleep)
- Female, age 25, 60 kg, 165 cm: BMR ≈ 1,345 kcal/day (≈ 56 kcal burned per hour of sleep)
- Male, age 45, 90 kg, 175 cm: BMR ≈ 1,774 kcal/day (≈ 74 kcal burned per hour of sleep)
- Female, age 35, 70 kg, 170 cm: BMR ≈ 1,427 kcal/day (≈ 59 kcal burned per hour of sleep)
When is a BMR calculator useful?
BMR is the starting point for weight management and nutrition planning. Knowing your BMR helps you determine your minimum calorie needs and tailor your diet to your goals — whether you want to lose weight, maintain your current weight, or build muscle. BMR is also used to calculate Total Daily Energy Expenditure (TDEE) by multiplying it by an activity factor.
What is the difference between BMR and TDEE?
BMR measures calories burned at complete rest (e.g. while sleeping). TDEE (Total Daily Energy Expenditure) includes BMR plus additional energy for physical activity and food digestion. TDEE is calculated by multiplying BMR by an activity multiplier ranging from 1.2 (sedentary) to 1.9 (extremely active). BMR is often confused with RMR (Resting Metabolic Rate) — RMR is measured after only a short rest period and runs roughly 10% higher than true BMR. In practice both terms are used interchangeably, but BMR is the stricter clinical measurement.
What can you do to increase your BMR?
Building muscle is the most effective way to raise BMR — muscle tissue burns roughly three times more calories at rest than fat tissue. Strength training 2–3 times per week, eating sufficient protein (1.6–2.2 g per kg of body weight), and staying well hydrated all support a higher resting metabolic rate. Use our ideal weight calculator to set a target weight range, and our sleep cycle calculator to optimise recovery. Age naturally lowers BMR, but regular resistance exercise significantly slows this decline.