How many calories should a cat eat per day?
A cat's calorie needs depend on body weight, body condition, and clinical status. RER provides the baseline estimate before maintenance or clinical adjustments.
Calculators / Nutrition
Cat Calorie Calculator
Calculate daily energy requirements for cats using RER (Resting Energy Requirement). This provides a baseline estimate that can be adjusted for maintenance, weight loss, or illness.
Calculate feeding plans, weight loss targets, and hospitalized nutrition.
Use Full Feeding PlannerOverview
Cats use the same RER formula used in general veterinary nutrition planning, but their feeding management is not the same as dogs. Feline patients have higher protein requirements, are less tolerant of prolonged calorie restriction, and require closer monitoring of actual intake.
In practice, calorie planning for cats also needs attention to anorexia history, body condition, and the risk of hepatic lipidosis if intake falls too low or weight loss is too rapid.
Formula
RER = 70 × (body weight in kg)^0.75
RER is the baseline metabolic energy requirement used in all veterinary nutrition planning. It provides the starting estimate before maintenance multipliers or clinical adjustments are applied.
Cat-specific multipliers
- Neutered adult cat: 1.2 × RER
- Intact adult cat: 1.4 × RER
- Weight loss: about 1.0 × RER of ideal weight
- Growth: 2.0–2.5 × RER
- Hospitalized: start at RER
Reference values
| Weight | RER | Maintenance |
|---|---|---|
| 3 kg | ~160 kcal/day | ~190 kcal/day |
| 4 kg | ~200 kcal/day | ~240 kcal/day |
| 5 kg | ~235 kcal/day | ~280 kcal/day |
Clinical note
Cats are sensitive to caloric restriction. Rapid weight loss can cause hepatic lipidosis, so diet changes should be introduced carefully and monitored closely.
When RER alone is not enough
RER is only the baseline estimate. Body condition score changes how calorie targets should be interpreted, especially in overweight or underweight cats.
Illness can also change energy needs, tolerance to feeding, and the urgency of nutritional support. In anorexic or hospitalized cats, calorie planning quickly becomes a clinical management issue rather than a simple maintenance calculation.
Related tools: fluid calculator and dose calculator.
Use the full feeding tool when you need more than a baseline estimate
The full DVMReady feeding planner applies this baseline to maintenance, weight loss, and hospitalized patients without duplicating calculations manually.
For canine energy calculations, use the dog calorie calculator.
Calculate feeding plans, weight loss targets, and hospitalized nutrition.
Use Full Feeding PlannerFrequently asked questions
What is RER in cats?
RER is Resting Energy Requirement. It is the baseline energy estimate used in veterinary nutrition planning for cats.
Can cats lose weight safely with calorie restriction?
Cats can lose weight safely with controlled calorie restriction, but the reduction must be gradual and monitored closely. Rapid restriction increases clinical risk.
Why is hepatic lipidosis a concern in cats?
Cats are vulnerable to hepatic lipidosis when intake drops or weight loss is too rapid. That is why anorexia and diet changes require close monitoring.