RER and MER Calculator
Our RER and MER calculator helps you understand and calculate your pet's Resting Energy Requirement (RER) and Maintenance Energy Requirement (MER). These are essential veterinary formulas used to determine your pet's daily calorie needs.
What is RER (Resting Energy Requirement)?
RER is the number of calories your pet needs at complete rest - essentially the base metabolic rate. It represents the minimum energy required for basic bodily functions like breathing, circulation, and cell maintenance.
RER Formula: RER = 70 × (weight in kg)^0.75
This formula is the standard veterinary calculation used for both dogs and cats.
What is MER (Maintenance Energy Requirement)?
MER is the total daily calories your pet needs including normal activity, digestion, and other metabolic processes. It's calculated by multiplying RER by activity and life stage factors.
MER Formula: MER = RER × Activity Factor × Life Stage Factor
RER Calculator
Results:
Estimated MER (Maintenance Energy Requirement):
Understanding RER and MER
RER (Resting Energy Requirement)
- Base metabolic rate at complete rest
- Minimum calories needed for basic bodily functions
- Formula: RER = 70 × (weight in kg)^0.75
- Same formula for dogs and cats
MER (Maintenance Energy Requirement)
- Total daily calories including normal activity
- Calculated by multiplying RER by activity factors
- Typical multipliers: 1.2 (low activity) to 2.0 (high activity)
- Life stage factors: Puppies/kittens need 1.5-2.5x, seniors need 0.8x
Activity Factors for MER
| Activity Level | Multiplier | Description |
|---|---|---|
| Low | 1.2 | Mostly indoor, minimal exercise |
| Moderate | 1.4-1.6 | Regular walks and play |
| High | 1.8-2.0 | Very active, working dogs |
Related Calculators
Use our other calculators for complete nutrition planning:
- Dog Nutrition Calculator - Complete calorie calculator for dogs
- Cat Nutrition Calculator - Complete calorie calculator for cats