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Resting Metabolic Rate (RMR) Calculator

Calculate your Resting Metabolic Rate (RMR).

Resting Metabolic Rate (RMR) Calculator

What is Resting Metabolic Rate (RMR)?

RMR refers to the number of calories your body burns while at rest over 24 hours. It differs slightly from Basal Metabolic Rate (BMR) but is often used interchangeably. RMR includes the calories burned by minimal physical activity like sitting or small movements, while BMR assumes complete rest. RMR accounts for roughly 60–75% of your daily energy expenditure, making it one of the most important numbers to know when managing your weight.

Why Does RMR Matter?

Knowing your RMR gives you a baseline for how many calories your body naturally needs to function. Once you see this number, you can:

  • Create a calorie deficit to lose weight
  • Add calories strategically to gain muscle
  • Maintain your weight by eating at your RMR + activity level
  • Avoid undereating, which can slow metabolism
RMR Calculator Formula

The most common and reliable formula to estimate RMR is the Mifflin-St Jeor Equation:

For Men: RMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5

For Women: RMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

Example:

A 35-year-old woman weighing 65 kg and 165 cm tall:

RMR = (10 × 65) + (6.25 × 165) − (5 × 35) − 161
= 650 + 1031.25 − 175 − 161
= 1,345.25 kcal/day

This means her body burns about 1,345 calories per day at rest.

Factors That Influence RMR
  • Age – RMR decreases with age
  • Gender – Men typically have a higher RMR due to more muscle mass
  • Body composition – More muscle = higher RMR
  • Genetics – Some people naturally burn more calories at rest
  • Hormones – Thyroid and other hormones can significantly impact RMR
  • Dieting history – Repeated extreme dieting may lower your metabolic rate
How to Use Your RMR

Once you've estimated your RMR, the next step is to factor in your physical activity level to determine your Total Daily Energy Expenditure (TDEE)—how many calories you burn daily. Multiply your RMR by an activity factor:

  • Sedentary (little/no exercise): RMR × 1.2
  • Light activity (1–3 days/week): RMR × 1.375
  • Moderate activity (3–5 days/week): RMR × 1.55
  • Active (6–7 days/week): RMR × 1.725
  • Very active (twice daily or intense training): RMR × 1.9

This gives you a more personalized calorie estimate for daily life.

RMR vs. BMR – What's the Difference?
BMR (Basal Metabolic Rate) RMR (Resting Metabolic Rate)
Measured under strict conditions (e.g., after 8 hours of sleep). Measured under less strict resting conditions
Does not include small movements. Includes small daily movements (e.g., sitting, digesting)
Slightly lower than RMR, marginally higher than BMR Used in clinical and lab settings, more practical for everyday use
How to Increase Your Resting Metabolic Rate
  • Build lean muscle mass with strength training
  • Stay active throughout the day (not just during workouts)
  • Avoid crash dieting, which can reduce metabolism
  • Get enough protein, which has a higher thermic effect
  • Sleep well to regulate metabolism-related hormones
  • Stay hydrated to support all bodily functions
Final Thoughts

Your Resting Metabolic Rate is the foundation of your body's calorie needs. Knowing this number helps you make smarter decisions about eating, exercising, and setting realistic goals—whether your aim is weight loss, muscle gain, or general wellness.

A simple RMR Calculator gives you powerful insight into how your body works. Use it as a guide, listen to your body, and make adjustments along the way.