Enter your height, weight, and age into the calculator to estimate your resting energy expenditure (REE).

REE (Harris–Benedict) Resting Energy Expenditure Calculator

This tool uses the original Harris–Benedict predictive equation (commonly used for BMR/REE-style estimates). Choose which equation to use for your estimate. Optionally, you can use the “solve” feature as an algebra tool: enter either Male REE or Female REE and leave exactly one of weight, height, or age blank to solve for the missing value (educational use only).

Disclaimer: This calculator provides an estimate only and is not medical advice or a diagnosis. Do not use it to set calorie intake for children/adolescents, pregnancy or breastfeeding, eating disorders, or medical conditions without guidance from a qualified clinician or registered dietitian.

REE Formula

The following Harris–Benedict predictive equations (original) can be used to estimate resting energy expenditure (REE) in kcal/day (with weight in kg, height in cm, and age in years). Predictive equations are rough estimates and can be off by ~10–20% for some individuals; some clinicians also use alternatives such as the Mifflin–St Jeor equation depending on the situation.

Males: 

REE (kcal/day) = 66.47 + 13.75 * (W) + 5 * (H) - 6.76 * (A)

Females: 

REE (kcal/day) = 655.1 + 9.563 * (W) + 1.85 * (H) - 4.676 * (A)
  • Where REE is resting energy expenditure (kcal/day)
  • W is weight (kg)
  • H is height (cm)
  • A is age (years)

REE Definition

REE stands for resting energy expenditure. It estimates the energy your body uses at rest to maintain vital functions (such as breathing and circulation), typically reported per day (kcal/day or kJ/day).

REE is closely related to basal metabolic rate (BMR). The two terms are often used interchangeably, but BMR is measured under stricter “basal” conditions and may differ slightly from REE.

Example Problem

How to calculate REE?

  1. First, determine your height.

    For this example, the person is measured to be 182.88 cm.

  2. Next, determine your weight.

    This person’s weight is measured to be 70kg.

  3. Next, determine your age.

    The person in this example is 20 years old.

  4. Finally, calculate the REE.

    Using the formula above, the resting energy expenditure is found to be:
    REE = 66.47 + 13.75 * (W) + 5* (H) – 6.76 * (A)
    REE = 66.47 + 13.75 * (70) + 5* (182.88) – 6.76 * (20)
    REE = 1808.17 kcal/day.

FAQ

What factors can affect my Resting Energy Expenditure (REE)?

Several factors can influence your REE, including age, sex, weight, height, body composition, and certain hormones and health conditions. Generally, more lean (muscle) mass is associated with a higher REE, while fat mass contributes less to REE than lean mass.

How often should I recalculate my REE?

It’s useful to recalculate after a significant change in body weight or body composition (for example, after noticeable weight loss or gain). Age changes slowly, and activity level affects total daily energy expenditure more than REE itself.

Can improving my REE help with weight loss?

Increasing REE can help modestly with weight loss because you burn more calories at rest. Strength training can increase or preserve lean mass, which is associated with a higher REE. However, overall weight loss still primarily depends on maintaining an appropriate calorie deficit.