Resting Metabolic Rate Calculator
Instantly calculate your resting metabolic rate (RMR) with the Mifflin-St Jeor formula. Find out how many calories you burn at rest - free, accurate, no sign-up. Supports pounds/kg and feet/cm.
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Calculator of Resting Metabolic Rate (RMR):
Calculator of Resting Metabolic Rate (RMR): Learn How Many Calories Your Body burn at Rest.
The Resting Metabolic Rate (RMR) - or Basal Metabolic Rate (BMR) - is one of the most significant numbers in the world of weight loss, muscle gain, and health in general. It is the calories that your body requires on a daily basis in order to survive: to get your heart pumping, your lungs breathing, your brain thinking, and your organs working even though you may have done nothing in the whole day but lying in bed.
The key to every successful nutrition program is knowing your actual RMR. Eat much less than it and you will lose weight. Eat at or slightly above it, and you'll maintain. Eat well above it, and you'll gain. It is just that, and that mighty.
This is why we created this free, correct Resting Metabolic rate Calculator based on the gold standard Mifflin-st Jeor equation- the formula that registered dietitians, doctors, and best health websites all over the world use.
What Is the Resting Metabolic Rate (RMR)?
The total calories that are burned by your body within a 24 hours time frame when you are in full rest is your RMR. It generally contributes 60-75 percent of the total number of calories burned each day - considerably more than exercise or movement.
Consider it in the following way: even when you are binge-watching your favorite show or sleeping, your body is burning hundreds of calories just to keep you alive. The higher your RMR, the more food you can eat without gaining weight.
Why Knowing Your RMR Matters More Than Ever
Most people guess their calorie needs using outdated rules like “multiply your weight by 11” or generic online calculators that haven't been updated in years. These guesses can be off by 300-600 calories per day - enough to completely stall fat loss or cause unintended weight gain.
With our RMR calculator, you get a personalized number based on:
Your gender
Your current age
Your exact height (in feet/inches or cm/meters)
Your current weight (in pounds or kilograms)
The scientifically validated Mifflin-St Jeor formula (published in 1990 and still the most accurate prediction equation available)
What the Results Actually Mean
Suppose that the calculator informs you that your RMR is 1,850 calories per day.
This does not imply that you should be consuming 1,850 calories only to maintain weight.
Why? And since you are not really resting all day. You walk, talk, labor, eat, chew food, and fidget. All these activities will give hundreds (and even thousands) of additional calories burned on top of your RMR.
The real number of calories that you use each day - Total Daily Energy Expenditure (TDEE) - is your RMR multiplied by an activity factor:
| Activity Level | Multiplier | Example (1,850 RMR) |
|---|---|---|
| Sedentary (little/no exercise) | × 1.2 | 2,220 calories |
| Lightly active (light exercise) | × 1.375 | 2,544 calories |
| Moderately active | × 1.55 | 2,868 calories |
| Very active (hard exercise) | × 1.725 | 3,191 calories |
| Extremely active (athlete) | × 1.9 | 3,515 calories |
So someone with a 1,850 RMR who works a desk job and exercises 3-4 times a week probably burns around 2,600-2,800 calories per day — not 1,850.
RMR formula and calculation example
Our calculator uses the Mifflin-St Jeor equation the most accurate and widely accepted formula in modern clinical practice (published 1990, validated in dozens of studies ever since).
Formula (in metric units cm and kg)
For Male
RMR (kcal/day) = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
For Female:
RMR (kcal/day) = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
This is the exact formula running behind our tool (all imperial values are automatically converted to metric before calculation).
Real Calculation Example
Let's calculate the RMR for a 35-year-old woman who is 5 ft 6 in (168 cm) tall and weighs 145 lbs (65.8 kg).
Convert to metric (if needed)
Height: 5 ft 6 in = 66 inches × 2.54 = 167.64 cm = 168 cm
Weight: 145 lbs ÷ 2.20462 = 65.77 kg = 65.8 kg
Plug into the Mifflin-St Jeor formula (female)
RMR = (10 × 65.8) + (6.25 × 168) - (5 × 35) - 161
= 658 + 1,050 - 175 - 161
= 1,708 - 175 - 161
= 1,533 - 161
= 1,372 kcal/day
So this woman burns approximately 1,372 calories per day at complete rest.
Same Example: For Male
If the exact same person were a 35-year-old man:
RMR = (10 × 65.8) + (6.25 × 168) - (5 × 35) + 5
= 658 + 1,050 - 175 + 5
= 1,538 kcal/day
Difference of 166 calories purely due to the sex variable in the formula that's why gender matters!
Use the calculator at the top of the page right now and see your own number in seconds it does all these conversions and math instantly.