Resting Metabolic Rate (RMR) is the number of calories your body burns at rest to maintain basic functions like breathing, circulation, and cell production. It accounts for 60–75% of total daily calorie expenditure.

Is RMR the same as BMR?

Not exactly. BMR (Basal Metabolic Rate) is measured under strict laboratory conditions (12-hour fast, complete rest). RMR is measured at rest but without those strict requirements. RMR is typically 3–5% higher than BMR. For practical purposes, they are very similar.

Which formula should I use?

If you do not know your body fat percentage, use Mifflin-St Jeor. If you know your body fat % and are lean/athletic, the Cunningham equation may be more accurate as it directly accounts for lean body mass.

NEAT (Non-Exercise Activity Thermogenesis) is the energy you burn through daily activities other than sleeping, eating, or structured exercise — things like walking, fidgeting, typing, and standing. It can range from 200 to 900+ kcal/day.

RMR Calculator

Name: RMR Calculator
Author: Manish Kumar

Key Takeaways

RMR (Resting Metabolic Rate) accounts for 60–75% of total daily energy expenditure in most people — it is the largest component of your calorie burn.^[1]
Three formulas are available: Mifflin-St Jeor (general), Cunningham (athletes with known BF%), and Katch-McArdle (LBM-based alternative).^[2]
RMR is ~3–5% higher than BMR. In practice, the terms are often used interchangeably, but RMR is more practical to measure.
NEAT (Non-Exercise Activity Thermogenesis) can vary by 200–900 kcal/day between individuals — a major factor in daily calorie burn variance.^[3]

The Three Formulas

Mifflin-St Jeor

10W + 6.25H − 5A ± s

Best for general populations without body composition data. See the dedicated Mifflin-St Jeor Calculator.

Cunningham

500 + 22 × LBM(kg)

Designed for athletes with known body fat %. Accounts for lean mass directly.

Katch-McArdle

370 + 21.6 × LBM(kg)

Alternative LBM-based formula. Produces slightly lower estimates than Cunningham.

RMR vs BMR: What is the Difference?

BMR (Basal Metabolic Rate) is measured under very strict conditions: 12-hour fast, complete rest, dark and thermoneutral room, immediately upon waking.

RMR (Resting Metabolic Rate) is measured at rest but without the strict fasting/overnight requirements. It is more practical for real-world settings and typically runs 3–5% higher than BMR.^[1]

For most tracking and planning purposes, the difference is negligible. Both terms are often used interchangeably in fitness contexts. For a multi-formula comparison, see the REE Calculator.

Understanding NEAT

NEAT (Non-Exercise Activity Thermogenesis) includes everything from fidgeting and walking to typing and standing. Research shows NEAT can account for 200–900+ kcal/day depending on occupation and individual behavior.^[3]

This means two people with identical RMR can have vastly different total daily burns based on their NEAT alone — a crucial factor often overlooked in calorie planning.

Limitations

All prediction equations have a standard error of ±200–300 kcal/day compared to indirect calorimetry.
Factors like thyroid function, medication, caffeine intake, and recent exercise affect actual RMR.
The Cunningham and Katch-McArdle formulas require accurate body fat % — self-reported BF% introduces additional error.
NEAT estimates are broad population ranges, not personalized measurements.
This tool is for informational and journaling purposes only. It does not constitute personalized advice.

Frequently Asked Questions

Sources & References

Resting metabolic rate: measurement reliability. Various. PMC (2023)
Predictive equations for resting energy expenditure. Various. Sci Rep (2023)
Non-exercise activity thermogenesis (NEAT). Various. PMC (2024)

Manish Kumar

Certified Personal Trainer & Sports Nutritionist

NASM-CPTCertified Sports Nutritionist10+ Years Experience500+ Clients Coached

NASM-certified fitness and nutrition coach with over 10 years of hands-on experience helping people build strength, lose fat, and live healthier lives. Specializing in gym-based workouts with a strong focus on lifting technique, biomechanics, and practical exercise science. Through FitLifeRegime, sharing the tools, tips, and insights that have worked for hundreds of clients — helping you start your own fitness journey with confidence and clarity.

Learn more about Manish

NASM Certified

Certified Personal Trainer & Sports Nutritionist from the National Academy of Sports Medicine

This tool is for informational and journaling purposes only.

I am NOT a doctor.

RMR (Resting Metabolic Rate) Calculator