Nutrition Diet: How do I find out my basal metabolic rate?

October 19, 2025 •

2 min read

According to the Cleveland Clinic, a person's basal metabolic rate (BMR) accounts for 60% to 70% of their total daily energy expenditure. For anyone pursuing health or fitness goals, understanding how do I find out my basal metabolic rate is the crucial first step to creating a personalized nutritional strategy.

Quick Summary

Learn the methods for determining your basal metabolic rate, from simple at-home calculation formulas to professional indirect calorimetry testing, to inform your diet and weight management goals effectively.

Key Points

BMR is the caloric baseline: Your BMR is the minimum number of calories your body burns at complete rest to stay alive and function properly.
Formulas offer reliable estimates: Use equations like the Mifflin-St Jeor or Revised Harris-Benedict with your age, weight, height, and sex for a good starting point.
Professional tests are more accurate: For the most precise measurement, indirect calorimetry can be performed by a professional to measure your unique metabolic rate.
Factors like muscle mass matter: Your BMR is heavily influenced by your body composition, with more muscle leading to a higher resting metabolism.
BMR informs your calorie goals: Convert your BMR to your Total Daily Energy Expenditure (TDEE) using an activity factor to guide your daily calorie intake for weight management.
Never eat below your BMR: Eating fewer calories than your BMR can be harmful, as it signals starvation to your body and slows down your metabolism.

Understanding the Basics: BMR vs. RMR

BMR and RMR (resting metabolic rate) are often used interchangeably, but BMR is measured under stricter conditions (after fasting and sleep) than RMR, which accounts for some low-effort activities. RMR is slightly higher and generally more practical for most individuals' use.

Method 1: Using Predictive Formulas at Home

Predictive equations offer a convenient way to estimate your BMR. The Mifflin-St Jeor equation is widely considered one of the most accurate for the general population.

Calculating your BMR at home typically involves using formulas like Mifflin-St Jeor or Revised Harris-Benedict, which factor in your age, weight, height, and sex. {Link: NASM https://www.nasm.org/resources/calorie-calculator} provides an overview of these methods.

Method 2: Professional Measurement

For maximum accuracy, indirect calorimetry is the preferred professional method.

How an Indirect Calorimetry Test Works

Preparation: Fast for over 12 hours and avoid strenuous activity.
The test: Rest while a device measures your oxygen consumption and carbon dioxide production.
The results: The measurement provides a precise BMR based on your individual metabolism.

Factors That Influence Your BMR

Several factors impact your BMR, including body composition, age, gender, genetics, diet, hormonal balance, and environmental temperature.

A Comparison of BMR Calculation Methods

A comparison of BMR calculation methods can be found on {Link: NASM https://www.nasm.org/resources/calorie-calculator}, detailing cost, accessibility, accuracy, and key factors considered for formulas like Mifflin-St Jeor, Revised Harris-Benedict, Indirect Calorimetry, and Cunningham Formula.

How to Use Your BMR to Achieve Your Goals

To determine your total daily energy expenditure (TDEE), multiply your BMR by an activity factor. Activity levels range from sedentary (BMR x 1.2) to extra active (BMR x 1.9).

Use your TDEE to guide your calorie intake for weight loss (eat below TDEE, but not below BMR), weight gain (eat above TDEE), or maintenance (eat near TDEE). Eating below your BMR can slow metabolism and cause health issues.

Conclusion: Taking Control of Your Nutritional Journey

Calculating your BMR provides essential information for managing your nutritional health and setting realistic goals. Whether using a formula or professional testing, combining your BMR with an activity factor to find your TDEE allows for informed dietary decisions. For personalized advice, consult a registered dietitian.

Frequently Asked Questions

BMR (Basal Metabolic Rate) is measured under very strict, controlled conditions of complete rest and fasting. RMR (Resting Metabolic Rate) is measured under more typical, relaxed conditions and is slightly higher (10-20%) because it includes some low-effort activities. RMR is more practical for most people's use.

The Mifflin-St Jeor equation is generally considered the most accurate of the common predictive formulas for estimating BMR in most people. It was developed in 1990 and is based on a larger, more diverse sample population than the older Harris-Benedict formula.

Yes, BMR tends to decrease with age. This is primarily due to a natural decline in lean muscle mass, as muscle tissue burns more calories at rest than fat tissue.

Yes, the most effective way to increase your BMR is to build lean muscle mass through strength or resistance training. Muscle is more metabolically active than fat, so increasing your muscle mass boosts your resting energy expenditure.

First, calculate your BMR using a formula. Then, multiply your BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE). To lose weight, you should consume fewer calories than your TDEE, but never below your BMR.

Eating below your BMR can cause your body to enter a starvation-protection mode, slowing down your metabolism to conserve energy. This can hinder weight loss efforts and potentially harm your health.

Both very cold and very warm environments can increase your BMR. In the cold, your body burns more energy to generate heat, while in the heat, it expends energy to cool itself down through processes like sweating.