How can I figure out my RMR?

October 14, 2025 •

3 min read

According to the American Society for Nutrition, a person's Resting Metabolic Rate (RMR) can account for 60–70% of their total daily energy expenditure. Learning how can I figure out my RMR is a fundamental step in crafting a personalized nutrition diet, empowering you to better understand your body's energy needs for weight management and health optimization.

Quick Summary

Determining your Resting Metabolic Rate (RMR) is crucial for a tailored nutrition plan. This guide explains how to calculate your RMR using widely accepted formulas or through professional testing, outlining the key differences and factors that influence your metabolic rate.

Key Points

RMR is your baseline calorie burn: Your Resting Metabolic Rate is the number of calories your body needs to perform vital functions while at rest, forming the foundation of your daily energy needs.
Use the Mifflin-St Jeor equation for home estimation: The Mifflin-St Jeor formula offers a reliable method for estimating RMR using your gender, weight, height, and age, providing an excellent starting point for nutritional planning.
Professional testing is the most accurate method: Indirect calorimetry, performed in a clinical setting, offers the most precise RMR measurement by analyzing your oxygen and carbon dioxide exchange.
RMR is influenced by body composition: Since muscle tissue is more metabolically active than fat, increasing your lean body mass through strength training is a key way to boost your RMR over time.
Create a caloric deficit for weight loss: To lose weight, subtract a set number of calories from your Total Daily Energy Expenditure (TDEE), which is calculated by multiplying your RMR by your activity factor.
Avoid severe calorie restriction: Drastic calorie cuts can lower your RMR by putting your body into survival mode, making long-term weight loss difficult.
A personalized nutrition diet depends on RMR: Using your RMR as a benchmark allows for a more effective, tailored dietary strategy for weight loss, maintenance, or gain, as opposed to a generic plan.

Understanding Resting Metabolic Rate (RMR)

Your RMR is the number of calories your body burns at rest to perform essential functions like breathing, circulation, and cell production. It's a baseline energy requirement and is often used interchangeably with Basal Metabolic Rate (BMR), although RMR is typically measured under less strict conditions.

How to Calculate RMR at Home: Formulas

Formulas using factors like age, gender, weight, and height can provide a highly accurate RMR estimate. The Mifflin-St Jeor equation is a widely used method. For the Mifflin-St Jeor formulas and a sample calculation, see {Link: NASM Blog https://blog.nasm.org/how-to-calculate-and-improve-rmr-resting-metabolic-rate}.

To determine your Total Daily Energy Expenditure (TDEE), multiply your RMR by an activity factor based on your physical activity level. Activity factors can be found on {Link: NASM Blog https://blog.nasm.org/how-to-calculate-and-improve-rmr-resting-metabolic-rate}.

Professional Measurement: Indirect Calorimetry

Indirect calorimetry is the most accurate way to measure RMR professionally. This involves analyzing the oxygen you consume and carbon dioxide you produce at rest to determine your precise resting calorie burn. This method is particularly useful for individuals with specific health needs or athletes. The test typically involves resting quietly with a mask or mouthpiece for 15-20 minutes while a machine analyzes your breath.

Factors That Influence Your RMR

Several factors can influence your RMR:

Lean Body Mass: Muscle burns more calories at rest than fat, so higher muscle mass increases RMR. Strength training can help increase lean body mass and RMR.
Age: RMR generally declines with age, partly due to muscle loss and hormonal changes.
Genetics and Hormones: Genetics and conditions like hypothyroidism can affect your RMR.
Calorie Restriction: Severe calorie cuts can lower RMR as the body conserves energy, potentially hindering long-term weight loss.
Sleep and Stress: Lack of sleep and high stress levels can negatively impact RMR by affecting hormone balance.
Environmental Temperature: The body burns extra energy to stay warm in cold conditions, temporarily increasing RMR.

RMR vs. BMR vs. TDEE: A Comparison

Here's a comparison of key metabolic rate terms:


Term	Measurement Conditions	What It Represents	Calculation Method
Basal Metabolic Rate (BMR)	Strict, controlled environment.	Minimum energy for vital functions.	Clinical measurement.
Resting Metabolic Rate (RMR)	Less restrictive conditions.	Energy burned at rest, including minimal activity.	Formulas or professional measurement.
Total Daily Energy Expenditure (TDEE)	Reflects all daily activities.	Total calories burned in a day.	RMR multiplied by activity factor.

Using Your RMR for a Smarter Nutrition Diet

Knowing your RMR helps create a personalized nutrition plan based on your energy needs.

For Weight Loss

To lose weight, consume fewer calories than your TDEE (a caloric deficit). Subtracting 500-1000 calories from your TDEE can lead to sustainable weight loss.

For Weight Maintenance

To maintain weight, match your daily calorie intake to your TDEE, adjusting as needed based on RMR and activity level.

For Weight Gain

To gain weight, especially muscle, consume more calories than your TDEE (a caloric surplus), with increased protein intake if strength training.

Optimizing Your Metabolism

Support a healthy metabolism through lifestyle choices. Resistance training builds muscle and increases RMR. Adequate sleep, stress management, and a consistent, nutritious diet also contribute to a healthy metabolism.

Conclusion

Figuring out your RMR is a crucial step for personalized nutrition. Whether you use a formula or professional testing, your RMR provides a baseline for tailoring your diet to meet your weight goals. Understanding and managing your RMR supports a sustainable and effective nutrition plan for long-term health. The Mifflin-St Jeor equation is a good starting point, while professional measurement offers the highest accuracy for specific needs {Link: NASM Blog https://blog.nasm.org/how-to-calculate-and-improve-rmr-resting-metabolic-rate}.

Frequently Asked Questions

While often used interchangeably, RMR (Resting Metabolic Rate) measures energy expenditure under less strict conditions than BMR (Basal Metabolic Rate). BMR is the energy burned at complete rest, while RMR accounts for minimal daily activities. RMR tends to be slightly higher than BMR and is easier to measure outside of a lab.

For home calculations, the Mifflin-St Jeor equation is generally considered more accurate and reliable than the older Harris-Benedict formula, though both provide useful estimates. The absolute most accurate method is indirect calorimetry in a clinical setting.

Your RMR is highly influenced by your body composition. Muscle is more metabolically active than fat, so individuals with more lean muscle mass burn more calories at rest. Building muscle through strength training is one of the most effective ways to increase your RMR.

Yes, you can increase your RMR through controllable factors. The most impactful way is to increase your lean muscle mass through regular resistance training. A healthy diet, adequate sleep, and managing stress levels also play a significant role.

First, calculate your Total Daily Energy Expenditure (TDEE) by multiplying your RMR by your activity factor. Then, create a modest caloric deficit by consuming 500-1000 fewer calories than your TDEE per day to promote gradual, sustainable weight loss.

When you drastically reduce your calorie intake, your body may lower its metabolic rate to conserve energy. This is a survival mechanism that can lead to a weight-loss plateau and makes it more difficult to lose weight long-term.

Online calculators that use established formulas like Mifflin-St Jeor provide a good estimate based on population averages. However, they are not as precise as a professional indirect calorimetry test, which accounts for your unique physiology.