Your resting metabolic rate (RMR) is the number of calories your body burns at rest to maintain basic functions like breathing, circulation, and cell production. Calculating your RMR is the foundation for determining total daily energy expenditure and creating effective nutrition and fitness plans tailored to your body's needs.
What Is Resting Metabolic Rate?
Resting metabolic rate represents the minimum calories your body needs daily just to exist. It accounts for 60-75% of total daily energy expenditure in sedentary individuals. Knowing your RMR helps you set appropriate calorie intake for weight loss, maintenance, or muscle gain.
RMR = calories burned at rest per day
TDEE = Total Daily Energy Expenditure (RMR + activity)
Mifflin-St Jeor Equation (Most Accurate)
The Mifflin-St Jeor equation is considered the most accurate for calculating RMR:
For Men:
RMR = (10 ร weight in kg) + (6.25 ร height in cm) - (5 ร age in years) + 5
For Women:
RMR = (10 ร weight in kg) + (6.25 ร height in cm) - (5 ร age in years) - 161
Worked Example: Male
Man: 30 years old, 180 lbs (81.8 kg), 5'10" (178 cm)
RMR = (10 ร 81.8) + (6.25 ร 178) - (5 ร 30) + 5
RMR = 818 + 1,112.5 - 150 + 5
RMR = 1,785.5 calories per day
Worked Example: Female
Woman: 28 years old, 140 lbs (63.6 kg), 5'5" (165 cm)
RMR = (10 ร 63.6) + (6.25 ร 165) - (5 ร 28) - 161
RMR = 636 + 1,031.25 - 140 - 161
RMR = 1,366.25 calories per day
Harris-Benedict Equation (Alternative)
An older but still useful equation:
For Men:
RMR = 88.362 + (13.397 ร weight in kg) + (4.799 ร height in cm) - (5.677 ร age)
For Women:
RMR = 447.593 + (9.247 ร weight in kg) + (3.098 ร height in cm) - (4.330 ร age)
RMR Examples Table
| Person | Age | Weight | Height | RMR |
|---|---|---|---|---|
| Man | 25 | 180 lbs | 5'10" | 1,850 |
| Woman | 25 | 140 lbs | 5'5" | 1,420 |
| Man | 50 | 180 lbs | 5'10" | 1,700 |
| Woman | 50 | 140 lbs | 5'5" | 1,280 |
| Athletic man | 30 | 200 lbs | 6'0" | 1,950 |
Factors Affecting RMR
| Factor | Impact |
|---|---|
| Age | RMR decreases ~2% per decade after 20 |
| Sex | Men typically have 5-10% higher RMR |
| Muscle mass | More muscle = higher RMR |
| Body composition | More lean mass = higher RMR |
| Genetics | 20-30% variation between individuals |
| Hormones | Thyroid, hormones affect metabolism |
| Medications | Some drugs affect metabolic rate |
Impact of Weight Changes on RMR
Losing weight reduces RMR because you have less body mass to maintain:
Expected RMR decrease โ 2-3% per 5-10 lbs lost
Example:
Starting RMR: 1,800 calories
After losing 15 lbs: 1,800 ร 0.94 = 1,692 calories
(Metabolic adaptation)
Total Daily Energy Expenditure (TDEE)
Once you know RMR, calculate total daily energy needs:
TDEE = RMR ร Activity Factor
Activity Factors:
Sedentary (little exercise): 1.2
Lightly active (1-3 days/week): 1.375
Moderately active (3-5 days/week): 1.55
Very active (6-7 days/week): 1.725
Extremely active (twice per day): 1.9
Example: Man with RMR of 1,800 calories
Sedentary: 1,800 ร 1.2 = 2,160 cal/day
Lightly active: 1,800 ร 1.375 = 2,475 cal/day
Moderately active: 1,800 ร 1.55 = 2,790 cal/day
Very active: 1,800 ร 1.725 = 3,105 cal/day
Weight Loss Calorie Deficit
To lose weight, create a calorie deficit:
Calorie deficit = TDEE - Target calories
Weight loss per week = Deficit รท 3,500 calories/lb
Example:
TDEE: 2,500 calories
Target for weight loss: 2,000 calories
Daily deficit: 500 calories
Weekly deficit: 3,500 calories
Expected weight loss: 1 lb per week
Muscle Building Calorie Surplus
To build muscle, create a calorie surplus:
Calorie surplus = Target calories - TDEE
Muscle gain (optimal): 300-500 calorie surplus
RMR Variations by Body Type
| Body Type | Typical RMR | Notes |
|---|---|---|
| Ectomorph (lean) | 15-18% above average | Fast metabolism |
| Mesomorph (athletic) | Average to above | Responds well to training |
| Endomorph (heavy) | 10-15% below average | Slower metabolism |
Improving Your RMR
Ways to increase resting metabolic rate:
| Strategy | Potential Increase |
|---|---|
| Build muscle (1 lb) | 6-10 calories/day |
| High-intensity training | 5-10% increase |
| Adequate protein | Thermic effect |
| Quality sleep | Normal metabolism |
| Manage stress | Prevent metabolic slowdown |
Metabolic Adaptation
Your body adapts to calorie deficits:
After extended dieting, RMR may decrease 10-25%
Refeed periods help restore metabolism
Gradual deficit is more sustainable
Using RMR for Different Goals
For Weight Loss:
TDEE - 500 cal = modest deficit = 1 lb/week loss
TDEE - 750 cal = aggressive deficit = 1.5 lb/week loss
(Not below RMR + 200)
For Muscle Gain:
TDEE + 300-500 cal = lean muscle gain
Focus on strength training with surplus
For Maintenance:
TDEE = weight maintenance
Monitor and adjust based on actual results
Real-World Example
30-year-old man:
Weight: 190 lbs (86.2 kg)
Height: 5'11" (180 cm)
Calculated RMR: 1,845 calories
Lifestyle: Moderately active (gym 4x/week)
TDEE: 1,845 ร 1.55 = 2,860 calories/day
Goal: Lose 20 lbs (maintain muscle)
Target: 2,360 calories/day (500 deficit)
Expected timeline: 20 weeks
Testing Your Actual RMR
Metabolic testing (indirect calorimetry) measures actual RMR, but calculations provide reasonable estimates. Results typically within 10-20% of calculated values.
Use our Resting Metabolic Rate Calculator to instantly calculate your RMR and create a personalized nutrition plan.