How much dry food should a cat eat? It depends on weight, age, and how active the cat is — and on the food itself, because dry food has a different calorie density from wet food. This guide works it out properly: the resting energy requirement (RER) formula vets use, the table for dry food at every weight, how to convert between calories and grams, and the pros and cons of dry food against wet food. Every figure is an estimate, and the tin or bag's number always wins over this guide's.
The short answer is that a typical neutered adult cat needs its daily calories in dry food, and a typical dry food is around 350 kcal per cup or per 100 g, so the grams follow from the calories. The table below gives the figure at every weight, so you can find your cat's row and read the number. The rest of this guide explains what the number means, how to use it, and when dry food is the better choice.
How many calories does a cat need?
Veterinary nutritionists start with the resting energy requirement, or RER — the calories a cat burns at rest in a neutral temperature, doing nothing at all. The formula is: RER equals 70 times body weight in kg to the power of 0.75. Daily needs are then the RER multiplied by a factor for life stage and activity: about 1.2 for a typical neutered adult cat, about 1.4 for an intact adult, about 1.4 to 1.6 for an active or outdoor cat, about 2.5 for a kitten, and about 1.1 to 1.4 for a senior.
For a cat of 5 kg, the RER is about 235 calories a day, so a typical neutered adult needs about 280 calories a day. These factors are the standard ones used in veterinary nutrition, but they are still starting points: a cat that is mostly a couch companion needs less than one that is out all day, and a cat that has been neutered typically needs about 10–20% fewer calories than before. The right amount is the one that keeps weight steady: weigh the cat monthly, and if weight drifts up, cut food by about 10% and re-weigh in a month rather than changing everything at once.
How much dry food per day
Use the row nearest your cat's weight. The grams figures assume a typical dry food at around 350 kcal per cup or per 100 g — a common figure, but your food may differ, and the tin or bag's number always wins over this guide's. If your food's kcal figure is different, divide the calories in the table by your food's kcal per 100 g and multiply by 100 to get the grams.
| Body weight | Calories (typical neutered adult) | Cups of dry food per day | Grams of dry food per day |
|---|---|---|---|
| 2 kg | 140 kcal | 0.4 cups | 40 g |
| 2.5 kg | 165 kcal | 0.5 cups | 47 g |
| 3 kg | 190 kcal | 0.5 cups | 54 g |
| 4 kg | 240 kcal | 0.7 cups | 69 g |
| 5 kg | 280 kcal | 0.8 cups | 80 g |
| 6 kg | 320 kcal | 0.9 cups | 91 g |
| 8 kg | 400 kcal | 1.1 cups | 114 g |
| 11 kg | 505 kcal | 1.4 cups | 144 g |
Dry food is calorie-dense, so a day's food in grams is small — a 20 kg dog needing 600 calories needs only about 170 g of dry food. That is why weighing dry food matters so much: a scoop that is a few grams too full is a large share of the day's ration, and a mug used as a measure can be half as much again as a real cup.
How to feed dry food
Split the daily amount into two meals for an adult cat — morning and evening — rather than one large meal. Dry food should be measured with scales or a measuring cup, not a mug or a handful, and it should be stored in a sealed container away from heat and light. Once opened, a bag should be used within a few weeks, because the fats in dry food go stale, and stale food is less appealing and less nutritious. Fresh water should always be available, and a pet fed dry food needs to drink more than one fed wet food, because dry food adds almost no water to the diet.
Mixed feeding is fine as long as the total calories add up: a day's food can be half dry and half wet, or dry in the morning and wet in the evening, as long as the two halves add up to the daily calories in the table above. The common mistake is to give a full measure of dry food plus a full tin of wet food, which roughly doubles the ration. The the how much wet food should a cat eat guide gives the amounts for the other form, and the the cat feeding chart by weight guide gives the same numbers in chart form.
Pros and cons of dry food
Dry food is convenient, easy to measure, easy to store, and cheaper per calorie than wet food. It keeps well once opened, it can be left in a puzzle feeder, and it is easy to take travelling. It is also the form most therapeutic diets come in, which matters if the pet ever needs one.
Dry food adds almost no water to the diet, so a pet fed only dry food must drink enough on its own — and many pets do not. It does not clean teeth reliably, whatever the bag says, and it can be hard to eat for a pet with dental pain or a sore mouth. A pet fed only dry food may also drink less than it should, which matters for kidney health.
The choice between wet and dry food is less important than the amount: a cat fed the right number of calories in either form, with fresh water always available, will do well, while a cat fed too much of either form will gain weight. Choose the form your cat eats well and that you can measure accurately, and take care of the teeth separately — brushing or vet-recommended dental care matters far more than the choice between wet and dry. If your cat has a health condition, ask your vet which form suits it: a cat with kidney disease often does better on wet food, because it adds water, while a cat that needs a therapeutic diet may only have a dry form available.
Common mistakes with dry food
The most common mistake is feeding by the tin or the bag's chart alone: charts are generous, because they are written for active animals and rounded up, so treat them as a maximum, not a target. The second is guessing the amount: a scoop is not a portion — a scoop in one house can be half as much again as a scoop in another, and that hidden extra is often the whole reason a pet is overweight. The third is leaving food down all day, which hides appetite changes that are often the first sign of illness. The fourth is treat creep: treats should stay under 10% of daily calories. The fifth is switching foods suddenly, which upsets digestion — change foods gradually over a week, mixing the old and new in increasing proportions.
For related reading, see the the how much wet food should a cat eat guide, the the cat feeding chart by weight guide, the cat food calculator, the how many calories should a cat eat per day guide, the cat ideal weight calculator, the feeding schedule generator.
Frequently asked questions
How much dry food should a cat eat per day?
A typical neutered adult cat of 5 kg needs about 280 calories a day, which is roughly 80 g of a typical dry food. Find your cat's weight in the table above for the exact figure, and adjust by body condition and your vet's advice.
How many times a day should I feed cat dry food?
Two meals a day for an adult cat, morning and evening. Kittens need three to four meals a day until about six months, then two. One large meal a day is not ideal, and leaving food down all day makes portion control and appetite monitoring much harder.
Is dry food better than wet food?
Neither is better in itself: wet food adds water and is often more appealing, while dry food is convenient, easy to measure, and cheaper per calorie. What matters most is whether the food is complete and balanced and whether the amount is right. Choose the form your cat eats well and that you can measure accurately, and take care of the teeth separately.
Can I mix wet and dry food?
Yes, as long as the total calories add up: a day's food can be half wet and half dry, or wet in the morning and dry in the evening, as long as the two halves add up to the daily calories in the table above. The common mistake is to give a full measure of dry food plus a full tin of wet food, which roughly doubles the ration.
How do I know if my cat is eating the right amount of dry food?
Weigh the cat monthly and feel the ribs: you should feel them easily under a thin layer of fat, and see a waist from above and from the side. If weight is steady and the cat is in good condition, the amount is right. If weight drifts up or down, change the amount by about 10% and re-weigh in a month.
How long does dry food keep once opened?
Dry food should be stored in a sealed container away from heat and light, and used within a few weeks of opening, because the fats in dry food go stale. Do not store it in a damp place, and do not feed food that smells stale or rancid.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.