How many calories does your cat need per day? Calculate using the veterinary RER formula — free, instant results.
Enter details above to calculate calories
RER = 70 × (body_weight_kg)0.75
Daily Calories = RER × Activity Factor × Body Condition Factor × Age Factor
| Weight (lbs) | Sedentary | Moderate | Active | Kitten | Senior |
|---|---|---|---|---|---|
| 5 lbs (2.3 kg) | 140 kcal | 168 kcal | 196 kcal | 252 kcal | 126 kcal |
| 8 lbs (3.6 kg) | 196 kcal | 235 kcal | 274 kcal | 353 kcal | 176 kcal |
| 10 lbs (4.5 kg) | 230 kcal | 276 kcal | 322 kcal | 414 kcal | 207 kcal |
| 12 lbs (5.4 kg) | 260 kcal | 312 kcal | 364 kcal | 468 kcal | 234 kcal |
| 15 lbs (6.8 kg) | 303 kcal | 364 kcal | 425 kcal | 546 kcal | 273 kcal |
| 18 lbs (8.2 kg) | 343 kcal | 412 kcal | 480 kcal | 618 kcal | 309 kcal |
| 20 lbs (9.1 kg) | 368 kcal | 442 kcal | 515 kcal | 663 kcal | 331 kcal |
RER stands for Resting Energy Requirement. It is the minimum energy a cat needs at complete rest in a thermoneutral environment. The standard formula is RER = 70 × (body weight in kg) to the power of 0.75. This is then multiplied by activity and health factors to get the total daily calorie need.
Kittens are growing rapidly and have higher metabolic rates. A kitten's calorie requirement is about 1.5x that of an adult cat of the same weight because they are building muscle, bone, and organ tissue. This high demand continues until they reach adult size around 12 months.
A standard 3-ounce (85g) can of wet cat food contains approximately 80-120 kcal. Premium brands tend toward the lower end (more protein, less filler), while economy brands may be higher. Always check the label for guaranteed analysis and metabolizable energy.
Most dry cat foods contain 350-450 kcal per cup (measuring cup). Higher-protein, grain-free foods tend to be more calorie-dense (400+ kcal/cup). Light or weight-management formulas are typically 280-340 kcal per cup. Check the bag label for exact values.
Both! Use calories to determine the total daily amount, then measure portions accordingly. This ensures accuracy regardless of food brand changes. Our Feeding Calculator converts calories into cups and cans for easy feeding.