How Much Dry Food to Feed a Cat Per Day, by Weight
An adult 4 kg (8.8 lb) cat, neutered or living indoors, needs about 190 kcal per day, which comes to roughly 50 g of a food with 3,800 kcal/kg. But the energy in adult cat food varies widely: across the 32 adult cat lines in our US catalog that declare kcal/kg, it runs from 3,171 to 4,358 kcal/kg, and the densest delivers 37% more calories per gram than the lightest (4,358 ÷ 3,171 = 1.37). The amount in grams changes with the food, not just with the cat.
How many grams of dry food should an adult cat eat per day?
It depends on the cat's weight and the food's kcal/kg. For a neutered or indoor cat of 3 to 5 kg (6.6 to 11 lb), the math gives 36 to 63 g per day across the foods in the chart below. FEDIAF treats the calculation as a starting point, to be adjusted if the cat gains or loses weight.
The energy estimate we use here comes from FEDIAF, the European pet food industry federation. In its 2024 guidelines, the average requirement of an adult neutered and/or indoor cat is 75 kcal per kg of body weight raised to the power 0.67, and an active cat's is 100. FEDIAF itself notes that many lean cats may need less energy ("many lean cats may need less energy").
A small error matters because a cat eats so little. Ten extra grams a day add up to 3.65 kg (8 lb) of food per year (10 g × 365 days). In a 3,800 kcal/kg food, those 10 g are 38 kcal, or 20% of the 190 kcal a day that a neutered 4 kg cat needs.
Do neutered cats eat less? How much less?
Yes, on average. For adult neutered and/or indoor cats, FEDIAF estimates 75 kcal per kg to the power 0.67, against 100 for the active adult cat. Table VII-9 of the same publication gives the neutered/indoor group a range of 52 to 75, and 75 is the top of it.
In calories, the difference is a quarter. The chart below applies both ends of the formula to the most common adult cat weights.
| Cat's weight | Neutered or indoor (75) | Active adult (100) |
|---|---|---|
| 3 kg (6.6 lb) | 157 kcal/day | 209 kcal/day |
| 4 kg (8.8 lb) | 190 kcal/day | 253 kcal/day |
| 5 kg (11 lb) | 220 kcal/day | 294 kcal/day |
For the 4 kg cat, FEDIAF gives 189 kcal (neutered/indoor) and 253 kcal (active) as an example. Our chart rounds the first value to 190. FEDIAF's group is "neutered and/or indoor". A neutered cat that burns a lot of energy can land above the left-hand column, and its body weight will show it.
How do you turn the food's kcal/kg into grams?
Divide the cat's daily kcal by the food's kcal/kg and multiply by 1,000. For a neutered 4 kg cat that needs 190 kcal, on a 3,800 kcal/kg food, the math is 190 ÷ 3,800 × 1,000 = 50 g per day. The kcal/kg is on the bag, under "calorie content".
For the four foods below, all from our US catalog with declared kcal/kg, the daily grams for a cat with the neutered/indoor requirement (75) come out like this:
| Food | kcal/kg | 3 kg cat | 4 kg cat | 5 kg cat |
|---|---|---|---|---|
| Hill's Science Diet Adult Indoor (chicken) | 3,492 | 45 g | 54 g | 63 g |
| Royal Canin Indoor Adult | 3,534 | 44 g | 54 g | 62 g |
| Purina ONE Indoor Advantage (turkey) | 3,756 | 42 g | 51 g | 59 g |
| Purina Pro Plan Adult Chicken & Rice | 4,358 | 36 g | 44 g | 51 g |
For the same 4 kg cat, the gap between the lightest and the densest food in the chart is 10 g a day (54 g against 44 g), or 3.65 kg a year. Switching brands without redoing the math delivers more or fewer calories in the same old scoop. The values here are for adult food; kittens and pregnant queens follow a different calculation and the bag's feeding chart.
To run the numbers with your own cat's weight and food, use the cat food cost and portion calculator. If you have not picked a food yet, the cat food quiz filters by your cat's profile.
Does leaving the bowl full all day work?
It depends on the cat, and the only proof is its weight. Cornell's College of Veterinary Medicine notes that dry food "offers owners the convenience" of "free choice" feeding. The same page says obesity is the most common nutrition-related problem in cats.
In practice, a full bowl with no measuring leaves the owner not knowing how many grams the cat eats. Measuring the daily portion and splitting it as your routine allows gives control back: if weight goes up, the portion goes down. Cornell recommends asking your veterinarian to help determine the ideal body weight for your cat and following their guidance to adjust the diet.
Treats count in the same math. Cornell suggests treats should not exceed 10 to 15 percent of daily calories, and that amount comes out of the food portion, not on top of it. To see what obesity asks of the food, read obese cat: is the food helping or hurting.
Frequently asked questions
Is the feeding chart on the bag wrong?
Not necessarily. The manufacturer's chart uses the energy of its own food and usually gives a range by weight, which works as a starting point. Compare it with the math above: if the bag suggests far more grams than the calculation for your cat, watch its weight over the following weeks and adjust.
Does wet food count in the math?
Yes, through calories. Pouches and cans have a different kcal per gram than dry food, because they carry much more water. Add up the kcal of everything the cat eats in the day and compare it with its requirement, instead of adding up grams of different products.
When should I see a veterinarian to adjust the portion?
Cornell recommends asking your veterinarian to help determine the ideal body weight for your cat and following their guidance to adjust the diet. The same page says a cat that refuses food and loses weight should be examined by a veterinarian. For cats that refuse their food, see what to do when a cat won't eat dry food.
Compare cat foods side by side → or see the cat food ranking →, always redoing the gram math when you switch brands.
Picked by score from our overall cat ranking, not by the topic of this article. To get it right for your pet — age, weight, spayed or neutered — take the quiz and get a list made for them. A pet with a diagnosed condition needs a diet prescribed by a veterinarian.
