How to Use This Calculator
- 1
Enter Your Weight (lbs)
Input your current body weight in pounds. This is a primary factor in calculating your Resting Energy Expenditure.
- 2
Enter Your Height (in)
Provide your height in inches. For example, 5 feet 10 inches would be 70 inches. Height also influences metabolic rate.
- 3
Input Your Age (yrs)
Enter your current age in years. Age is a significant factor, as metabolic rate generally declines with advancing age.
- 4
Select Your Gender
Choose your biological gender (Male or Female), as the Mifflin-St Jeor equation uses different coefficients for each.
- 5
Review Your Results
The calculator will display your daily, hourly, weekly, and monthly REE, along with Total Daily Energy Expenditure (TDEE) estimates for various activity levels.
Example Calculation
An individual who is 170 lbs, 70 inches tall, 35 years old, and male wants to find their Resting Energy Expenditure.
Weight (lbs)
170
Height (in)
70
Age (yrs)
35
Gender
male
Results
1712 kcal/day
Tips
Interpreting REE for Weight Management
Your REE represents the minimum calories your body needs to function. To lose weight, aim for a caloric deficit of 300-500 kcal/day below your TDEE, not just REE, for a sustainable loss of 0.5-1 lb per week.
Boosting Your REE
Building muscle mass can naturally increase your REE. Each pound of muscle burns approximately 6-10 calories per day at rest, compared to 2-3 calories for fat tissue.
REE vs. BMR
While often used interchangeably, REE is typically 10-20% higher than Basal Metabolic Rate (BMR) because it's measured under less strict conditions (e.g., after a light meal) compared to BMR's strict fasting and rest requirements.
Calculate Your Resting Energy Expenditure (REE) for Personalized Nutrition
The Resting Energy Expenditure (REE) Calculator utilizes the widely accepted Mifflin-St Jeor equation to estimate the calories your body burns at rest each day.
By inputting your weight, height, age, and gender, the tool provides your daily, hourly, weekly, and monthly REE, along with crucial Total Daily Energy Expenditure (TDEE) estimates across various activity levels.
This is a foundational metric for anyone looking to manage their weight, optimize their fitness regimen, or understand their baseline metabolic needs, typically accounting for 60-75% of total daily calorie burn.
Why Knowing Your Resting Energy Expenditure Matters
Understanding your Resting Energy Expenditure (REE) is a cornerstone of effective nutrition and fitness planning.
It provides the baseline number of calories your body requires simply to exist, powering essential functions like breathing, circulation, and cell repair.
Without knowing this fundamental metabolic rate, any attempts at calorie tracking for weight loss or gain are largely guesswork.
For example, if your REE is 1700 kcal/day, consuming only 1200 kcal/day might create an unhealthy deficit, while consuming 2500 kcal/day could lead to weight gain if your activity level doesn't justify it.
Knowing your REE empowers you to set realistic and sustainable calorie targets for your goals.
The Mifflin-St Jeor Equation for REE Calculation
The Mifflin-St Jeor equation is recognized as one of the most accurate predictive formulas for Resting Energy Expenditure (REE).
It takes into account body weight, height, age, and gender, applying specific coefficients to each variable.
For Men:
REE = (10 × Weight in kg) + (6.25 × Height in cm) - (5 × Age in years) + 5
For Women:
REE = (10 × Weight in kg) + (6.25 × Height in cm) - (5 × Age in years) - 161
Where:
- Weight is converted from pounds to kilograms (
lbs × 0.453592). - Height is converted from inches to centimeters (
inches × 2.54).
Calculating Resting Energy Expenditure: A Worked Example
Let's calculate the REE for a male individual with the following characteristics:
- Weight:
170 lbs - Height:
70 inches(5 ft 10 in) - Age:
35 years - Gender: Male
Step-by-step calculation:
- Convert Weight to kg:
170 lbs × 0.453592 = 77.11 kg. - Convert Height to cm:
70 inches × 2.54 = 177.8 cm. - Apply Mifflin-St Jeor (Male):
REE = (10 × 77.11) + (6.25 × 177.8) - (5 × 35) + 5REE = 771.1 + 1111.25 - 175 + 5REE = 1712.35 kcal/day
The individual's Resting Energy Expenditure is approximately 1712 kcal/day.
This means their body burns about 1712 calories daily just to maintain basic functions.
BMR vs. REE: Understanding Your Baseline Calorie Burn
While often used interchangeably, Basal Metabolic Rate (BMR) and Resting Energy Expenditure (REE) have subtle but important distinctions.
BMR is measured under very strict conditions: after a 12-14 hour fast, in a thermoneutral environment, and after a full night's sleep, typically in a clinical setting.
It represents the absolute minimum energy required for life.
REE, on the other hand, is measured under less stringent conditions, often after a 4-hour fast and 30 minutes of rest, making it more practical for common use.
Consequently, REE is typically 10-20% higher than BMR because it includes the energy expended during light activity or digestion of a recent meal.
For most adults, REE accounts for roughly 60-75% of their Total Daily Energy Expenditure (TDEE).
Clinical Use of REE in Nutritional Assessment
Resting Energy Expenditure (REE) is a critical metric for healthcare professionals, particularly registered dietitians and physicians, in clinical nutritional assessment and patient management.
In 2025, predictive equations like Mifflin-St Jeor are widely adopted by organizations such as the Academy of Nutrition and Dietetics for estimating REE in various patient populations, including those with obesity, metabolic syndrome, or critical illnesses.
For instance, in intensive care units, precise REE measurements (often obtained via indirect calorimetry) guide the amount of enteral or parenteral nutrition provided, preventing both underfeeding (which can lead to malnutrition and delayed recovery) and overfeeding (which can cause hyperglycemia and excess carbon dioxide production).
Accurate REE assessment is also vital for developing personalized weight management plans, ensuring calorie targets are realistic and support long-term adherence.
Frequently Asked Questions
What is Resting Energy Expenditure (REE)?
Resting Energy Expenditure (REE) is the number of calories your body burns at rest over a 24-hour period to maintain basic physiological functions like breathing, circulation, body temperature, and cell production. It accounts for the majority of your total daily calorie burn, typically ranging from 60-75% of an average adult's Total Daily Energy Expenditure (TDEE). REE is slightly higher than Basal Metabolic Rate (BMR) due to less stringent measurement conditions.
How is REE calculated using the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is a widely used formula to estimate REE. For men, the formula is (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5. For women, it's (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161. This equation is considered more accurate than older formulas like Harris-Benedict for many populations.
What is the difference between REE and TDEE?
REE (Resting Energy Expenditure) is the calories burned at rest, covering essential bodily functions. TDEE (Total Daily Energy Expenditure) includes your REE plus the calories burned from physical activity (exercise, daily movement) and the thermic effect of food (digestion). TDEE is your total daily calorie burn, crucial for weight management, and is typically 1.2 to 1.9 times your REE depending on activity level.
How accurate are REE calculators?
REE calculators using predictive equations like Mifflin-St Jeor provide good estimates but are not perfectly accurate for everyone. They can have an error margin of 10-20% compared to direct measurements (e.g., indirect calorimetry). Individual variations in metabolism, body composition, and genetics mean that these calculators serve as useful starting points for nutritional planning, but may require adjustment based on real-world results.