Cat Food Calculator
Work out how many calories your cat needs and turn them into grams of kibble and cans of wet food. Choose the life stage and activity level, mix wet and dry in any ratio and see portions per day and per meal.
For a diet, enter the target weight.
0 = only dry food, 100 = only wet food.
Printed on the bag (typical 3,500–4,200).
A 3 oz (85 g) can is often 70–100 kcal.
How to use the Cat Food Calculator
- Enter your cat’s weight in kg or lb (for a diet, the target weight).
- Pick the life stage and activity level that fit your cat.
- Copy the calories from the food labels: kcal per kg for dry food and kcal per can for wet food.
- Set the wet food share (0% for dry only, 100% for wet only) and meals per day.
- Press Calculate portions and adjust over the next weeks based on your cat’s weight.
How the cat calorie formula works
Veterinary nutrition guidelines start with the resting energy requirement (RER), the energy a cat uses at rest:
RER = 70 × (body weight in kg)0.75
The daily energy requirement is RER multiplied by a factor for life stage and lifestyle. Portions then follow from the calorie density on the label: grams of dry food = kcal ÷ kcal per kg × 1,000 and cans of wet food = kcal ÷ kcal per can.
Example: a 4.5 kg neutered adult has RER = 70 × 4.50.75 ≈ 70 × 3.09 ≈ 216 kcal, and 216 × 1.2 ≈ 260 kcal per day. Half from wet food (130 kcal ÷ 85 kcal ≈ 1.5 cans) and half from 3,800 kcal/kg kibble (130 ÷ 3,800 × 1,000 ≈ 34 g).
Daily calories by weight (neutered adult, factor 1.2)
| Weight | RER | Daily kcal | Dry food at 3,800 kcal/kg | Cans at 85 kcal |
|---|---|---|---|---|
| 2.5 kg (5.5 lb) | 139 | 167 | 44 g | 2.0 |
| 3 kg (6.6 lb) | 160 | 192 | 50 g | 2.3 |
| 3.5 kg (7.7 lb) | 179 | 215 | 57 g | 2.5 |
| 4 kg (8.8 lb) | 198 | 238 | 63 g | 2.8 |
| 4.5 kg (9.9 lb) | 216 | 260 | 68 g | 3.1 |
| 5 kg (11 lb) | 234 | 281 | 74 g | 3.3 |
| 6 kg (13.2 lb) | 268 | 322 | 85 g | 3.8 |
| 7 kg (15.4 lb) | 301 | 361 | 95 g | 4.3 |
Indoor, less active cats often need less than these figures. Treat the result as a starting point, weigh your cat regularly and ask your vet about the ideal weight and diet.
Frequently asked questions
How many calories does a cat need per day?
Most healthy indoor adult cats of about 4–5 kg (9–11 lb) need roughly 200–250 kcal per day. The usual estimate is the resting energy requirement RER = 70 × body weight in kg^0.75, multiplied by a life stage factor such as 1.2 for a neutered adult.
What life stage factors does the calculator use?
Common veterinary starting points: kitten under 4 months 3.0, kitten 4–12 months 2.5, neutered adult 1.2, intact adult 1.4, senior 1.1, weight loss 0.8 (of the target weight's RER), weight gain 1.4 and late pregnancy 2.0. Activity changes the result by about 10%.
How much wet food should I feed my cat?
Divide the wet food calories by the calories per can. A 4.5 kg neutered adult cat needing about 260 kcal would eat about 3 cans of an 85 kcal, 3 oz can per day if fed wet food only.
How many grams of dry food should a cat eat?
Divide the daily calories by the food's kcal per kg and multiply by 1,000. At 3,800 kcal/kg, 260 kcal is about 68 g of kibble per day. Always check the kcal on your bag because foods vary a lot.
Can I mix wet and dry cat food?
Yes. Decide what share of calories comes from each food, for example 50/50, and the calculator splits the portions so the total calories stay the same.
How much should I feed a cat to lose weight?
Use the target weight, not the current weight, with a factor of about 0.8 × RER, and aim for slow loss of about 1–2% of body weight per week. Fast weight loss is dangerous for cats, so plan any diet with your vet.
Are treats included?
Tick the treat option to keep 10% of the daily calories for treats, a common guideline. The meal portions are reduced so the total stays the same.