How do I calculate my resting energy?

December 29, 2025 •

3 min read

Resting energy expenditure (REE) accounts for 60% to 75% of your total daily calorie burn. This vital metric, also known as resting metabolic rate (RMR), represents the calories your body expends to maintain basic functions like breathing, circulation, and temperature regulation, even while you are at complete rest. Knowing your REE is the foundation for creating an effective diet and exercise plan for weight loss, maintenance, or gain.

Quick Summary

This guide provides step-by-step instructions on how to calculate your resting energy expenditure (REE) using common formulas, distinguishing it from basal metabolic rate (BMR). It explains the factors that influence your metabolic rate and explores methods for boosting your resting calorie burn.

Key Points

Differentiate REE/RMR from BMR: REE/RMR measures calories burned at light rest, whereas BMR is a stricter lab measurement for absolute rest.
Use Mifflin-St Jeor for accuracy: This modern equation is more reliable for estimating resting energy than the older Harris-Benedict formula.
Boost metabolism with muscle: Strength training builds muscle, which is more metabolically active and increases your resting calorie burn.
Calorie restriction lowers metabolism: Drastically cutting calories can trigger metabolic adaptation, causing your body to burn fewer calories at rest.
Protein intake increases TEF: Consuming more protein boosts the thermic effect of food (TEF), meaning your body uses more energy for digestion.
Sleep and hydration are critical: Poor sleep and dehydration can negatively impact your metabolic rate, so prioritizing both is essential.
HIIT elevates post-workout burn: High-intensity interval training can keep your metabolism elevated for hours after a session, contributing to a higher overall calorie expenditure.

Understanding Resting Energy: REE vs. BMR

Before learning how to calculate your resting energy, it's helpful to understand the key terminology. Resting energy expenditure (REE) is often used interchangeably with resting metabolic rate (RMR) and basal metabolic rate (BMR), but they have slight differences.

Basal Metabolic Rate (BMR): This is the minimum number of calories your body needs to stay alive and function at a basic level. BMR measurements are typically taken in a highly controlled, clinical setting after a full night's sleep and a 12-hour fast, requiring total rest and a specific thermal environment.
Resting Metabolic Rate (RMR) / Resting Energy Expenditure (REE): RMR is the number of calories your body burns while at rest, but under less strict conditions than BMR. It is measured after a night's sleep and a brief period of fasting, accounting for light daily activities like sitting up or digestion. RMR is more practical for everyday use and is typically about 10% higher than BMR. For general fitness and nutrition planning, RMR and REE are the most useful calculations.

Step-by-Step Guide to Calculating Resting Energy (RMR)

Calculating your resting energy can be done with a simple equation. The Mifflin-St Jeor equation is considered more accurate than the older Harris-Benedict formula, especially for modern populations, and is widely recommended. The Mifflin-St Jeor equation and an example calculation, as well as the Harris-Benedict equation, can be found on {Link: NASM website https://www.nasm.org/resource-center/blog/resting-metabolic-rate-how-to-calculate-and-improve-yours}. While the Harris-Benedict formula is older, it still provides a decent estimate but may slightly overestimate energy needs.

Factors Influencing Your Resting Energy

Several elements beyond just your size and age affect how many calories you burn at rest:

Muscle Mass: Individuals with more muscle mass burn more calories at rest as muscle is more metabolically active than fat. Strength training increases this.
Age: RMR declines with age, partly due to decreased fat-free mass.
Body Composition: The muscle-to-fat ratio significantly impacts RMR; increasing lean mass boosts metabolism.
Genetics: Heredity influences metabolism.
Diet: Severe calorie restriction can lower RMR (metabolic adaptation). Adequate protein helps counter this.
Sleep: Lack of sleep disrupts metabolism-regulating hormones.

Comparison of RMR Calculation Methods


Feature	Mifflin-St Jeor Equation	Harris-Benedict Equation	Indirect Calorimetry (Clinical)
Accuracy	More accurate for modern populations.	Less accurate, tends to overestimate.	The "gold standard" for measuring RMR directly.
Availability	Accessible via online calculators or self-calculation.	Widely available via online tools.	Requires specialized equipment in a clinical setting.
Practicality	High, suitable for everyday use in fitness and nutrition planning.	High, but with slightly less reliable results than Mifflin-St Jeor.	Low, impractical for routine tracking but used for high-precision needs.

Optimizing Your Resting Energy

Once you have calculated your RMR, you can use this baseline to manage your weight and health. For those looking to increase their metabolic rate, simple lifestyle changes can have a significant impact.

List of strategies to optimize resting energy:

Prioritize Strength Training: Building muscle increases RMR because muscle burns more calories at rest than fat.
Eat Enough Protein: Adequate protein boosts the thermic effect of food (TEF) and preserves muscle during weight loss.
Stay Hydrated: Drinking water can temporarily increase metabolism.
Incorporate High-Intensity Interval Training (HIIT): HIIT leads to EPOC, where your body burns calories at an elevated rate post-workout.
Manage Stress: Chronic stress can negatively impact metabolism through elevated cortisol levels.
Get Quality Sleep: Sufficient sleep regulates hormones affecting appetite and metabolism.

Conclusion

Calculating your resting energy is a powerful first step toward understanding your body's unique metabolic needs. By using a modern equation like the Mifflin-St Jeor formula, you can establish an accurate baseline for your daily calorie burn. This knowledge, combined with strategic lifestyle adjustments like increasing muscle mass, optimizing protein intake, and prioritizing sleep, empowers you to take control of your health and achieve your weight management goals more effectively. Consistent tracking and adjustments based on your progress are key to success.

Frequently Asked Questions

RMR (Resting Metabolic Rate) is the number of calories burned while at rest under normal, less-controlled conditions, accounting for minimal activity like digestion. BMR (Basal Metabolic Rate) is a more precise lab measurement of calories burned at complete rest in a specific thermal environment, after a prolonged fast.

The Mifflin-St Jeor equation is widely considered more accurate for modern populations than the older Harris-Benedict formula. However, both are estimations, and the gold standard for precision remains clinical indirect calorimetry.

You can increase your resting energy expenditure by building muscle mass through strength training, eating enough protein, drinking plenty of water, and getting adequate sleep. Regular physical activity, especially high-intensity interval training (HIIT), also helps boost your metabolic rate.

Yes, severely restricting your calorie intake can cause your resting metabolic rate to drop. This is known as metabolic adaptation, where your body conserves energy in response to a drastic reduction in food intake.

Yes, you can estimate your RMR using predictive equations like the Mifflin-St Jeor formula, which uses your age, sex, weight, and height. While not as precise as clinical measurements, it provides a practical starting point for general health goals.

Resting energy expenditure (REE) is the largest component of your total daily energy expenditure (TDEE), typically accounting for 60% to 75% of the total calories you burn each day.

Resting energy naturally declines with age, in part due to a decrease in muscle mass. On average, men tend to have a higher RMR than women because they generally have a higher proportion of muscle mass.