Resting Metabolic Rate Calculator

Understanding Resting Metabolic Rate

Resting Metabolic Rate (RMR), sometimes called Basal Metabolic Rate (BMR), is the number of calories your body needs to maintain basic physiological functions at rest. This includes breathing, circulation, cell production, nutrient processing, and protein synthesis.

The Mifflin-St Jeor Equation

This calculator uses the Mifflin-St Jeor equation, developed in 1990 and considered the most accurate formula for estimating RMR:

Why RMR Matters

Understanding your RMR is crucial for:

• Weight Management: Knowing your baseline calorie needs helps create effective diet plans
• Fitness Goals: Calculate calories needed for muscle building or fat loss
• Nutritional Planning: Ensure adequate nutrition without overeating
• Understanding Metabolism: Learn how your body uses energy

TDEE: Total Daily Energy Expenditure

Your TDEE is calculated by multiplying your RMR by an activity factor:

Activity Level	Factor	Description
Sedentary	1.2	Desk job, little to no exercise
Lightly Active	1.375	Light exercise 1-3 days/week
Moderately Active	1.55	Moderate exercise 3-5 days/week
Very Active	1.725	Hard exercise 6-7 days/week
Extra Active	1.9	Very hard exercise or physical job

Factors That Affect Metabolic Rate

Age

Metabolism naturally decreases with age, typically by about 1-2% per decade after age 20, partly due to loss of muscle mass.

Body Composition

Muscle tissue burns more calories than fat tissue, even at rest. This is why strength training can help boost metabolism.

Gender

Men typically have higher metabolic rates due to greater muscle mass and less body fat on average.

Hormones

Thyroid hormones, in particular, play a major role in regulating metabolism. Conditions like hypothyroidism can significantly slow metabolic rate.

Using RMR for Weight Goals

For Weight Loss

Create a calorie deficit by consuming 500-1000 calories less than your TDEE for 1-2 pounds of weight loss per week. Never go below your RMR.

For Weight Gain

Consume 300-500 calories more than your TDEE for gradual muscle gain, combined with strength training.

For Maintenance

Consume approximately your TDEE to maintain current weight.