Resting Calorie Needs Assessment
BMR Calculator

Determine your Basal Metabolic Rate (BMR) to establish a baseline for weight loss, maintenance, or gain goals.

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Daily Calorie Needs by Activity Level

Activity LevelCaloriesDescription
Sedentary0Little or no exercise
Light0Exercise 1-3 times/week
Moderate0Exercise 4-5 times/week
Active0Daily exercise or intense exercise 3-4 times/week
Very Active0Intense exercise 6-7 times/week
Extra Active0Very intense exercise daily, or physical job

Deep Dive into Basal Metabolism

Learn the science behind your body's resting energy expenditure and the formulas used to calculate it.

What is BMR?

Basal Metabolic Rate (BMR) is the amount of energy your body needs to maintain basic, vital functions at complete rest, like breathing and blood circulation. It accounts for ~70% of daily calorie burn.

BMR vs. RMR

BMR is measured under strict lab conditions (full rest, fasting). Resting Metabolic Rate (RMR) uses less strict criteria and is the more common, practical term for calories burned at rest.

Mifflin-St Jeor Formula

  • Key Variables:m=mass (kg), h=height (cm), a=age (years), s=+5 for men / -161 for women.

Physiology & Organs

The BMR is driven by internal organs, with the Liver (~27%) and Brain (~19%) being the largest energy consumers. Metabolism involves energy-releasing Catabolism and energy-requiring Anabolism.

Health & Fitness

Explore Other Metabolic Tools

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Quick Answers

Frequently Asked Questions (FAQs)

Get clarity on what BMR is, how it differs from RMR, and how you can influence it.

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Basal Metabolic Rate (BMR) is the amount of energy your body needs to maintain basic bodily functions at rest, such as breathing, blood circulation, body temperature control, cell growth, and brain function. It's the energy your body expends when you are completely at rest.
Your BMR accounts for about 70% of your daily calorie expenditure. A higher BMR means your body burns more calories at rest, which significantly influences whether you maintain, gain, or lose weight.
BMR is influenced by several factors, including age (it declines after age 20), sex, height, weight, lean body mass (muscle mass), genetics, and health conditions.
BMR and RMR are very similar and often used interchangeably. BMR is measured under strict, clinical conditions (complete rest, fasting). RMR is a more common measurement that uses less strict criteria and is typically used for practical daily planning.