Resting energy estimate

RMR Calculator — Resting Metabolic Rate

Estimate daily resting energy expenditure with the original Harris-Benedict-style equations stored on this page.

Personal inputs

Enter age and body measurements

RMR
Energy summary

Resting energy estimate

Your resting estimate will appear here

Choose the equation category and enter age, height, and weight.

Daily energy estimate built from body measurements and resting energy use
This equation predicts energy use; indirect calorimetry is a different, measured method.

What is Resting Metabolic Rate?

The Resting Metabolic Rate (RMR) Calculator estimates the number of calories your body burns at rest to maintain essential functions such as breathing, blood circulation, and body temperature regulation. It uses your age, gender, height, and weight to estimate your daily resting energy expenditure.

Understanding your RMR can help you learn more about your body's energy needs and plan your nutrition goals. However, RMR represents only the energy your body uses at rest, not the total calories you burn throughout the day.

How to Use This Calculator

This calculator uses your personal measurements to estimate your resting metabolic rate.

  • Gender: Select male or female according to the formula's available categories.
  • Age: Enter your age in years.
  • Height: Enter your height in centimeters, feet, inches, or meters.
  • Weight: Enter your weight in kilograms or pounds.

The calculator converts height into centimeters and weight into kilograms before applying the appropriate equation for the selected gender.

The result is rounded to the nearest whole number and expressed as an estimated number of calories per day (kcal/day).

Formula Used

This calculator uses the original Harris-Benedict equations for estimating resting energy expenditure.

RMR Formula for Men

RMR = 66 + (13.7 × Weight in kg) + (5 × Height in cm) − (6.8 × Age in years)

RMR Formula for Women

RMR = 655 + (9.6 × Weight in kg) + (1.8 × Height in cm) − (4.7 × Age in years)

These equations estimate daily resting energy expenditure using age, height, and weight. They are the original Harris-Benedict equations, rather than the revised equations published in 1984.

Variables Explained

Gender: Determines which of the two Harris-Benedict equations the calculator applies.

Age: Your age in years. Age is included because estimated resting energy expenditure changes throughout life.

Height: Your height, converted into centimeters before the calculation.

Weight: Your body weight, converted into kilograms before the calculation.

RMR: Your estimated resting metabolic rate, expressed in kilocalories per day (kcal/day).

Calories (kcal): A unit of energy. In nutrition, the word calories generally refers to kilocalories.

Worked Example

Suppose a man has the following measurements:

  • Gender: Male
  • Age: 30 years
  • Height: 175 cm
  • Weight: 70 kg

Step 1: Select the formula for men.

RMR = 66 + (13.7 × Weight) + (5 × Height) − (6.8 × Age)

Step 2: Substitute the measurements.

RMR = 66 + (13.7 × 70) + (5 × 175) − (6.8 × 30)

Step 3: Calculate each term.

13.7 × 70 = 959

5 × 175 = 875

6.8 × 30 = 204

Step 4: Calculate the final result.

RMR = 66 + 959 + 875 − 204

RMR = 1,696 kcal/day

Why Use This Calculator?

The estimated resting metabolic rate is 1,696 calories per day. This represents the estimated energy required to support essential bodily functions at rest, not the person's total daily calorie requirement.

How to Interpret the Result

Your RMR estimates how much energy your body uses while at rest. It can provide a useful starting point for understanding your daily energy needs.

  • Lower RMR: Indicates a lower estimated resting energy requirement. This may be associated with factors such as smaller body size or differences in body composition.
  • Higher RMR: Indicates a higher estimated resting energy requirement. This may be associated with factors such as larger body size or greater metabolically active tissue.

There is no single ideal RMR value for everyone. Age, height, weight, body composition, genetics, and other individual factors can influence resting energy expenditure.

RMR is not the same as total daily energy expenditure (TDEE). Your total daily calorie needs also include physical activity, exercise, and the energy used to digest food.

If you want to estimate your maintenance calories, you need to consider your activity level in addition to your RMR. RMR alone should not be used as a personalized calorie target or as a substitute for professional nutrition advice.

Common Mistakes

1. Selecting the wrong height unit

Always select the correct unit for your height. For example, entering 175 while selecting meters instead of centimeters will produce an incorrect result.

2. Selecting the wrong weight unit

The calculator converts pounds into kilograms. Make sure you select the correct weight unit to avoid calculation errors.

3. Entering an incorrect age

Age is an important part of both equations. Enter your age in years rather than months or another unit.

4. Confusing RMR with TDEE

RMR estimates energy expenditure at rest, whereas TDEE estimates total daily energy expenditure, including activity and other daily energy requirements.

5. Assuming the result is an exact measurement

The calculator provides an estimate based on a predictive equation. Your actual resting energy expenditure may differ because of individual physiological factors.

6. Using RMR as a complete diet plan

Your RMR does not account for every aspect of your nutrition and activity needs. Avoid making major dietary changes based only on this number.

Frequently Asked Questions

<h3>What is resting metabolic rate (RMR)?</h3>

Resting Metabolic Rate (RMR) is the amount of energy your body uses at rest to maintain essential functions such as breathing, circulation, and temperature regulation.

What formula does this RMR calculator use?

This calculator uses the original Harris-Benedict equations. The equation for men is 66 + (13.7 × weight in kg) + (5 × height in cm) − (6.8 × age). The equation for women is 655 + (9.6 × weight in kg) + (1.8 × height in cm) − (4.7 × age).

<h3>What is the difference between RMR and BMR?</h3>

RMR stands for Resting Metabolic Rate, while BMR stands for Basal Metabolic Rate. Both estimate the energy needed to maintain essential bodily functions at rest. BMR is measured under stricter standardized conditions, whereas RMR testing generally allows somewhat less restrictive conditions.

<h3>How many calories do I burn at rest?</h3>

The number of calories you burn at rest depends on factors such as age, height, weight, body composition, and individual physiology. Enter your measurements into this calculator to estimate your resting energy expenditure in kcal/day.

<h3>Does RMR include exercise calories?</h3>

No. RMR estimates the energy your body uses at rest. Calories burned through exercise, walking, work, and other daily activities contribute to your total daily energy expenditure.

<h3>Can I use my RMR to lose weight?</h3>

RMR can help you understand your resting energy needs, but weight management depends on total energy expenditure, food intake, health, and other factors. RMR alone does not determine how many calories you should eat to lose weight.

<h3>Does a higher RMR mean a faster metabolism?</h3>

A higher RMR means your body is estimated to use more energy at rest. However, comparisons should account for body size, body composition, age, and other individual differences.

<h3>Can my RMR change over time?</h3>

Yes. RMR can change with changes in body weight, body composition, age, health status, and other physiological factors. Predictive equations provide estimates rather than direct measurements.

<h3>Is this RMR calculator accurate?</h3>

This calculator provides an estimate using the original Harris-Benedict equations. Predictive equations cannot precisely measure every individual's metabolism, so actual resting energy expenditure may be higher or lower than the result.

<h3>What is a normal RMR?</h3>

There is no single normal RMR value for everyone. Resting energy expenditure varies according to age, body size, body composition, and other individual characteristics. Your result should be interpreted in the context of your overall health and energy needs.

Sources & References