Your body burns calories even when you do nothing. Breathing, circulating blood, and keeping your temperature steady all use energy. That minimum energy is your basal metabolic rate (BMR), and it is the starting point for almost every calorie plan.
What Is BMR?
BMR is the number of calories your body needs at complete rest over 24 hours. For most people, it makes up roughly 60-70% of total daily energy use. BMR is not the same as your daily calorie target, because it does not include movement or exercise.
The BMR Formula (Mifflin-St Jeor)
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Worked Example
A 35-year-old woman, 70 kg, 168 cm:
- 10 × 70 = 700
- 6.25 × 168 = 1,050
- 5 × 35 = 175
- BMR = 700 + 1,050 − 175 − 161 = 1,414 calories per day
What Affects Your BMR?
- Muscle mass: muscle burns more energy at rest than fat.
- Age: BMR tends to decline gradually with age.
- Body size: larger bodies need more energy.
- Sex: men usually have a higher BMR, partly due to more lean mass.
- Genetics and hormones: thyroid function can raise or lower it.
Skip the Math
Enter your age, height, and weight into a free BMR calculator for an instant result. Then turn that number into a daily target with a TDEE calculator, or get a ready-made estimate from the calorie calculator.
How to Support a Healthy Metabolism
- Do strength training 2-3 times per week to maintain muscle.
- Eat enough protein and do not crash diet.
- Sleep 7-8 hours, since poor sleep affects appetite hormones.
- Do not eat below your BMR for long periods without medical advice.
FAQ
Is BMR the same as RMR? Almost. Resting metabolic rate (RMR) is measured under slightly less strict conditions, and the values are usually close.
Can I increase my BMR? Building muscle can raise it modestly over time. Extreme claims about “boosting metabolism” with supplements are mostly marketing.
How accurate is the formula? It is an estimate and can be off by 10% or more for some people.
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