Resting Metabolic Rate (RMR) Calculator
RMR approximates the calories you burn at rest. Use it to set maintenance calories, evaluate deficits or surpluses, and calibrate activity multipliers.
Optional but required for Cunningham equation.
Resting Metabolic Rate
1783 kcal/day
- • Mifflin–St Jeor equation (commonly used for resting metabolic rate).
- • Estimated lean mass: 67 kg.
RMR assumes complete rest in a thermoneutral environment. Multiply by an activity factor (1.2–1.9) to estimate total daily energy expenditure.
How to Use This Calculator
Pick a formula
Use Mifflin–St Jeor for general use. Harris–Benedict is included for comparison. Cunningham is best for trained athletes who know body composition.
Estimate activity multiplier
After calculating RMR, multiply by an activity factor (sedentary 1.2 → very active 1.8+) to get daily maintenance calories.
Track and adjust
Monitor weight trends for 2–4 weeks. If weight drifts, adjust calorie intake by 100–200 kcal/day and reassess.
Formula
Mifflin–St Jeor: RMR = 10×weight(kg) + 6.25×height(cm) − 5×age + (5 ♂ / −161 ♀)
Harris–Benedict: RMR = 66.5 + 13.75×weight + 5.003×height − 6.775×age (♂) or 655.1 + 9.563×weight + 1.850×height − 4.676×age (♀)
Cunningham: RMR = 370 + 21.6 × Lean mass (kg)
- Lean mass calculated from body weight and body fat where provided.
- RMR differs from REE (resting energy expenditure) or BMR measured in labs but is functionally similar.
- Use indirect calorimetry for the most accurate measurement when clinical precision is required.
Full Description
Resting Metabolic Rate represents the energy needed to maintain vital functions at rest: breathing, circulation, organ activity. It forms the foundation of calorie planning for fat loss, recomposition, or performance. While the calculator estimates RMR, real-world expenditure also includes thermic effect of food and activity calories.
Recalculate every few months or after significant weight changes. Combine RMR insights with resistance training, adequate protein, and sleep hygiene to support metabolic health. Consult dietitians or physicians when managing medical conditions or extreme weight goals.
Frequently Asked Questions
How accurate are these formulas?
They provide estimates within ±10%. For clinical accuracy, use indirect calorimetry or metabolic testing.
Why is my wearable showing different numbers?
Wearables estimate based on heart rate and activity. Use the calculator as a baseline and reconcile with long-term weight observations.
Should I eat exactly my RMR for weight loss?
No. RMR is the minimum. Eating at or below RMR can be unsustainable. Apply a moderate deficit relative to total daily energy expenditure.
What if I do not know my body fat percentage?
Leave it blank and use Mifflin or Harris. If you want to use Cunningham, estimate body fat with calipers, smart scales, or DEXA scans.