Select Gender:
Enter Height (cm):
Enter Weight (kg):
Enter Age:
Your body burns calories while you are sleeping. Our free BMR calculator will tell you just how many. Enter your gender, age, height, and weight. Calculate your BMR in seconds. Want to know that number for your diet and goals?
What Is a BMR Calculator?
A BMR calculator finds your basal metabolic rate. That is the number of calories your body burns just to stay alive. No exercise. No movement. Just basic body functions running in the background.
Think of it like your body’s electric bill. It keeps the lights on whether you move or not. Basal metabolic rate takes up 60 to 70% of the calories you burn every day. So it matters a lot.
How to Use the BMR Calculator
This free online BMR calculator is easy to use. You only need four details about yourself.
- Pick your gender.
- Enter your height
- Enter your weight
- Type your age
- Hit calculate
You will see your resting calorie needs right away. That number is what your body needs daily with zero activity. Think of it as your starting point.
What the Mifflin-St Jeor Equation Does
Our calculator uses the Mifflin-St Jeor equation. This is the most trusted BMR formula. The number you see is not made up. It comes from a real formula that scientists have studied and tested for many years.
The BMR Formula for Men and Women
This calculator uses the Mifflin-St Jeor equation. Research shows it gives better results than the old Harris-Benedict formula that was used for decades before it.
Gender | Formula |
Men | BMR = (10 x weight kg) + (6.25 x height cm) – (5 x age) + 5 |
Women | BMR = (10 x weight kg) + (6.25 x height cm) – (5 x age) – 161 |
Real example: A 30-year-old woman. She is 165 cm tall and weighs 60 kg.
BMR = (10 x 60) + (6.25 x 165) – (5 x 30) – 161 = 1,220 calories per day
That is how much her body burns at full rest. Zero movement added yet.
Factors That Affect Your Basal Metabolic Rate
Not everyone burns the same calories at rest. A lot of things change your basal metabolic rate. Here is what plays the biggest role:
- Muscle mass: More muscle means more calories burned at rest. Simple as that.
- Age: The older you get, the slower your BMR gets. Muscle drops with age.
- Biological sex: Men burn more at rest on average. They carry more muscle.
- Thyroid hormones: Very low metabolism caused by slow thyroid.
- A crash diet: Your body seeks to conserve when you restrict your food intake too severely for extended periods.
- Poor sleep and elevated cortisol levels decrease resting calories.
Lean body mass accounts for most influence on BMR. The higher the number, the more muscle you have.
BMR vs RMR: What Is the Difference?
People who expend more calories while sitting around will have a higher BMR. This can help you to control your body weight.
BMR is measured in a lab after a 12-hour fast with zero movement. RMR (resting metabolic rate) is tested in a relaxed setting. It comes out a little higher than BMR.
Our BMR calculator provides you with a BMR-equivalent output. The difference in their magnitudes is insignificant for daily use.
How to Use Your BMR for Weight Loss or Muscle Gain
Your BMR for weight loss is not the number you eat at. It is just the floor. You have to add your daily activity on top of it first.
Multiply your BMR by an activity factor to find your TDEE (total daily energy expenditure). Try our TDEE calculator to get that number fast.
Activity Level | Multiply BMR By |
Sedentary (little or no exercise) | 1.2 |
Lightly active (1 to 3 days a week) | 1.375 |
Moderately active (3 to 5 days a week) | 1.55 |
Very active (6 to 7 days a week) | 1.725 |
Extra active (hard training plus a physical job) | 1.9 |
After determining your TDEE, here’s what you need to do next:
- Lose fat: Consume 300-500 fewer calories than your TDEE.
- Diet for muscle building: Eat 200-300 calories more than your TDEE
- Stay the same: Match your TDEE
Break those calories into protein, carbs, and fat in the correct proportions with our macro calculator. The perfect weight calculator will assist you in picking a desired weight to work towards.
Frequently Asked Questions
Is a higher BMR better or worse?
People who are more active while sitting will have a higher BMR. This can help you maintain your weight more easily. It is not good or bad on its own. It just tells you how your body runs.
Can my BMR change over time?
Yes. Building muscle raises it. Losing muscle lowers it. Long-term dieting can also lower your BMR if you cut calories too hard for too long.
How accurate is an online BMR calculator?
The Mifflin-St Jeor formula used here is considered the most reliable for healthy adults. It gives a close estimate. For a clinical reading, a calorimetry test done at a doctor’s office is more precise.
When to recalculate BMR?
Recalculate weight loss or gain every 4-8 weeks. Your BMR changes with your body, so it’s important to keep it updated so you can stay on track.
Does BMR include calories burned during exercise?
No. BMR only covers what your body burns at complete rest. Exercise calories sit on top of that. Your TDEE Calculator adds both together for your full daily burn.