Pet Calorie Calculator
Precise RER & MER calculations for your pet
Calorie Breakdown
Understanding RER and MER
RER (Resting Energy Requirement) is the number of calories your pet needs at complete rest — just to maintain basic body functions like breathing, circulation, and cell repair.
Formula: RER = 70 × (weight in kg)0.75
MER (Maintenance Energy Requirement) is the actual daily calories needed, which factors in activity, life stage, and other variables:
Formula: MER = RER × Life Stage Factor
Life Stage Multipliers
| Life Stage | Dog Factor | Cat Factor |
|---|---|---|
| Neutered adult | 1.6 | 1.2 |
| Intact adult | 1.8 | 1.4 |
| Inactive/obese-prone | 1.2-1.4 | 1.0 |
| Weight loss | 1.0 | 0.8 |
| Active/working | 2.0-5.0 | 1.6 |
| Young puppy/kitten | 3.0 | 2.5 |
| Older puppy/kitten | 2.0 | 2.0 |
| Pregnant | 1.6-2.0 | 1.6-2.0 |
| Lactating | 2.0-6.0 | 2.0-6.0 |
| Senior | 1.2-1.4 | 1.1 |
Using Your Results
Once you know your pet's daily calorie needs, divide by the kcal/cup (or kcal/can) listed on your pet food label to determine portion size. Remember:
- Treats count! Subtract treat calories from the daily total
- Monitor weight every 2-4 weeks and adjust by 10% if needed
- These are starting points — individual pets vary by up to 25%
Related Tools
- Dog Food Calculator — Convert calories to cups
- Cat Food Calculator
- Pet BMI Calculator — Is your pet at ideal weight?