RMR Calculator – Resting Metabolic Rate
Calculate your Resting Metabolic Rate (RMR) to understand how many calories your body burns at rest. RMR represents the minimum energy required to maintain vital body functions like breathing, circulation, and cellular metabolism. This calculator uses proven scientific formulas to provide accurate estimates for weight management, fitness planning, and nutritional guidance.
Harris-Benedict
Mifflin-St Jeor
Katch-McArdle
The Harris-Benedict equation is one of the most widely used formulas for calculating RMR. It takes into account age, gender, weight, and height to provide accurate metabolic rate estimates.
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RMR (calories/day)
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TDEE (calories/day)
0
Weight Loss (1 lb/week)
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Weight Gain (1 lb/week)
Activity Level Multipliers
Sedentary: Little or no exercise, desk job
×1.2
Lightly Active: Light exercise 1-3 days per week
×1.375
Moderately Active: Moderate exercise 3-5 days per week
×1.55
Very Active: Hard exercise 6-7 days per week
×1.725
Extra Active: Very hard exercise, physical job, or training twice per day
×1.9
RMR Comparison by Method
| Method | Best For | Accuracy | Requirements |
|---|---|---|---|
| Harris-Benedict | General population | ±5-10% | Age, weight, height, gender |
| Mifflin-St Jeor | Most accurate for general use | ±5% | Age, weight, height, gender |
| Katch-McArdle | Athletes, lean individuals | ±3-5% | Lean body mass or body fat % |
Frequently Asked Questions
What is the difference between RMR and BMR?
RMR (Resting Metabolic Rate) and BMR (Basal Metabolic Rate) are very similar. BMR is measured under strict laboratory conditions after 12 hours of fasting and 8 hours of sleep. RMR is measured under less restrictive conditions and is typically 10-20% higher than BMR.
Which formula is most accurate?
The Mifflin-St Jeor equation is generally considered the most accurate for the general population. The Katch-McArdle formula is more accurate for lean individuals and athletes when body fat percentage is known. Harris-Benedict is the oldest but still widely used formula.
How do I use RMR for weight management?
Your Total Daily Energy Expenditure (TDEE) = RMR × Activity Level. To lose 1 pound per week, eat 500 calories below your TDEE. To gain 1 pound per week, eat 500 calories above your TDEE. Never eat below your RMR for extended periods.
How often should I recalculate my RMR?
Recalculate your RMR when your weight changes by 5+ pounds, when your activity level changes significantly, or every 3-6 months. Age-related changes in metabolism are gradual and typically don’t require frequent recalculation.
Can medications affect my RMR?
Yes, certain medications can affect metabolism. Thyroid medications, stimulants, beta-blockers, and some antidepressants can influence your metabolic rate. Consult with a healthcare provider for personalized advice if you take medications that may affect metabolism.
[Read More: Resting Metabolic Rate]
