BMR Calculator
Find your basal metabolic rate (BMR) with two trusted formulas and see your calorie needs at each activity level.
What Is a BMR Calculator?
A BMR calculator estimates your basal metabolic rate, the number of calories your body burns at complete rest to keep you alive. Breathing, circulation, cell repair and body temperature all use this energy. Searching for a BMR calculator is a smart first step before setting calorie goals for weight loss, maintenance or muscle gain.
BMR Formulas We Use
This tool shows two well-known equations. The Mifflin-St Jeor equation is widely considered the most reliable for modern adults. The revised Harris-Benedict equation is an older standard that often gives slightly higher numbers. Both use your sex, age, height and weight. For a 35-year-old woman who is 5 feet 6 inches and 160 pounds, Mifflin-St Jeor gives a BMR of about 1,437 calories a day.
What Affects Your BMR?
- Body size: larger bodies burn more calories at rest.
- Muscle mass: muscle burns more energy than fat, even when resting.
- Age: BMR tends to fall gradually as we age, partly from muscle loss.
- Sex: men usually have higher BMR because of more lean mass.
- Genetics and hormones: thyroid function and other factors play a role.
From BMR to Daily Calories
BMR is not the number of calories you should eat. Multiply it by an activity factor to find your total daily energy expenditure (TDEE), the calories you burn including movement and exercise. The table above does this for five activity levels. For weight loss, eat a modest amount below your TDEE, not below your BMR for long periods.
How to Support a Healthy Metabolism
Strength training helps maintain muscle, which supports your resting burn. Eat enough protein, sleep seven to nine hours and avoid crash diets, which can lower muscle mass and energy. Be cautious with products that promise to boost metabolism dramatically, since effects are usually small.
Frequently Asked Questions
What is a normal BMR?
Many adult women fall between about 1,200 and 1,600 calories a day and many men between 1,600 and 2,000, but body size makes a big difference.
Is BMR the same as RMR?
They are very close. Resting metabolic rate (RMR) is measured under less strict conditions and is usually slightly higher.
Can I raise my BMR?
Building muscle through resistance training is the most effective natural way to nudge it up over time.
Estimates only. Talk to a healthcare professional before changing your diet.