How much food should an adult cat eat? It depends on weight, age, and how active the cat is — not on the breed name alone. A typical neutered indoor adult cat of 4 kg needs about 240 calories a day, a 3 kg cat about 190, and a 6 kg cat about 320, and an active, outdoor, or intact cat needs more than a quiet indoor one of the same weight. This guide is the adult cat food calculator in words: the resting energy requirement (RER) formula vets use, the calorie table for adult cats at different weights, grams per day, feeding by life stage, and the mistakes that most often lead to an overweight adult cat. It uses the standard veterinary factors for cats and labels every figure as a starting point, not a prescription.
The adult years are when feeding mistakes show up most clearly, in one direction above all: weight gain. A cat that has stopped growing but keeps eating kitten amounts, or that becomes indoor-only while its food stays the same, will put on weight a few grams at a time until its ribs are hard to feel and its waist has gone. That extra weight is not harmless — in cats it is linked to diabetes, joint problems, and urinary issues — and it is much easier to prevent than to take off. Weigh the cat monthly, measure food with scales, and use the tables below as a starting point, then adjust by body condition: you should be able to feel the ribs easily under a thin layer of fat and see a waist from above and from the side.
How many calories does an adult 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 indoor adult, 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. So a typical neutered indoor cat of 4 kg has an RER of about 200 calories, and at the 1.2 factor it needs about 240 calories a day — against about 300 for the same cat living an active outdoor life, and about 500 for the same cat as a kitten.
These factors are the standard ones used in veterinary nutrition, but they are still starting points. A cat that sleeps most of the day indoors needs less than one that hunts, climbs, and plays for hours, and a cat that has been neutered typically needs about 10 to 20% fewer calories than before, so expect to cut food a little after the operation and watch the waistline for the next few months. 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. If weight drifts down without a change in food, mention it to your vet promptly — unexplained weight loss in an adult cat is always worth checking, and it is not solved by simply feeding more.
Adult cat daily calories by weight
Use the table below to find your adult cat's daily calories. Find the row nearest the cat's weight, then pick the column that matches the cat's life. A kitten's row is different — see the kitten cat food calculator guide — and a pregnant or nursing cat needs considerably more, which your vet should set individually. If your cat is between two rows, take the lower figure first: it is easier to add food to a cat that is losing weight than to take weight off a cat that has gained it, and cats gain weight easily when food is guessed rather than measured.
| Body weight | Neutered indoor adult (×1.2) | Intact adult (×1.4) | Active / outdoor (×1.5) | Weight loss (×0.9) | | --- | --- | --- | --- | | 2 kg | 140 | 165 | 175 | 105 | | 3 kg | 190 | 225 | 240 | 145 | | 4 kg | 240 | 275 | 295 | 180 | | 5 kg | 280 | 330 | 350 | 210 | | 6 kg | 320 | 375 | 405 | 240 | | 8 kg | 400 | 465 | 500 | 300 |
Note that calories are the real target and grams are only a translation. Different foods have very different calorie densities, so always check the kcal per 100 g on your own bag or tin and work from that. The grams figures below assume a typical dry food at around 350 kcal per 100 g — a common figure, but your food may differ, and the packet's number always wins over this guide's. If your cat is a large breed such as a Maine Coon at 6 to 11 kg, a Ragdoll at 5 to 9 kg, or a Savannah at 5 to 11 kg, use the higher rows of the table; if it is a small breed such as a Singapura at 2 to 3 kg, use the lower rows. Breed matters less than weight, though — the table is by weight, and weight is what the calories follow.
How much food in grams per day
For a neutered indoor adult cat, the daily amount in grams of a typical dry food at 350 kcal per 100 g is roughly as follows. A 2 kg cat needing about 140 calories needs roughly 40 g a day. A 4 kg cat needing about 240 calories needs roughly 70 g. A 6 kg cat needing about 320 calories needs roughly 90 g. The full table is below.
| Body weight | Calories (neutered indoor adult) | Grams of dry food per day |
|---|---|---|
| 2 kg | 140 kcal | 40 g |
| 3 kg | 190 kcal | 54 g |
| 4 kg | 240 kcal | 69 g |
| 5 kg | 280 kcal | 80 g |
| 6 kg | 320 kcal | 91 g |
| 8 kg | 400 kcal | 114 g |
Split the daily amount into two meals — morning and evening — or use a puzzle feeder so the cat works for its food, which slows eating and adds mental stimulation. If you feed wet food, use the tin's kcal figure to convert: a typical wet food is around 70 to 100 kcal per 100 g, so a 4 kg cat needing 240 calories would need roughly 280 g of wet food a day. Mixed feeding is fine as long as the total calories add up — the common mistake is to give a full measure of dry food plus a full pouch of wet food, which roughly doubles the ration. Measure food with scales, not a scoop or a handful: 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 an adult cat is overweight. Treats count too: they should stay under 10% of daily calories, which for a 4 kg cat is under about 25 calories of treats a day — a few small treats, not a handful.
Feeding an adult cat by stage
The junior stage, from 1 to 2 years, is when the cat is still maturing in behaviour and body, roughly equivalent to a person from 15 to 24. Energy is high, play is intense, and this is the best age for training good habits — including the habit of measured food. A junior cat that has just come off kitten food needs its amount cut to the adult factor of about 1.2, and the switch from kitten food to adult food should be gradual, over a week, mixing the old and new food in increasing proportions. The adult cat age calculator guide explains the life stages the feeding follows, and the kitten cat food calculator guide covers the kitten year that comes before.
The prime stage, from 3 to 6 years, is the adult peak: weight should be stable, the cat should be at its physical peak, and a vet check once a year is enough for most cats. This is the stage where weight most often creeps up, because the cat has stopped growing but the owner keeps feeding kitten amounts, or because the cat becomes indoor-only while food stays the same. Two meals a day, a complete adult food, measured amounts, and a monthly weigh-in are the whole of the plan, and they work — as long as they are actually done, every day, rather than just intended. The mature stage, from 7 to 10 years, is the equivalent of a person in their mid-forties to mid-fifties: weight can creep up further, activity can drop, and vet checks should start to include weight, teeth, and blood pressure. From 11, the cat is a senior, and the senior cat food calculator guide takes over.
Common feeding mistakes with adult cats
The most common mistake is free-feeding — leaving a full bowl of dry food down all day. It makes it impossible to know how much the cat has eaten, it hides appetite changes that are often the first sign of illness, and it is the fastest route to an overweight adult cat. The second is feeding by the packet's chart alone: packet charts are generous, because they are written for active cats and rounded up, so treat them as a maximum, not a target. The third is treat creep: a treat here, a piece of cheese there, and the cat's daily calories rise by a quarter without anyone noticing. The fourth is milk: most adult cats cannot digest lactose well, and milk is not a substitute for water — fresh water should always be available, in a clean bowl, away from the litter tray, and a water fountain is worth trying if your cat prefers running water.
The fifth mistake is switching foods suddenly, which upsets digestion — change foods gradually over a week, mixing the old and new in increasing proportions. The sixth is feeding a dog food, or a vegetarian diet, to a cat: cats are obligate carnivores, so their food must contain animal protein and nutrients such as taurine and arachidonic acid that cats cannot make themselves, and a dog food does not provide them. The seventh is ignoring the litter tray as a health signal: a cat that is eating too much or too little, or that has a health problem, often shows it first in the litter tray — changes in frequency, amount, or consistency are worth mentioning to a vet. If your cat has a health condition, ask your vet or a veterinary nutritionist before choosing a special diet — therapeutic diets are medicines in food form and should not be chosen by guesswork.
Foods an adult cat should never eat
Some everyday foods are toxic to cats and should never be given, in any amount: onions, garlic, leeks, and chives; chocolate and cocoa; grapes and raisins; xylitol, also called birch sugar, found in some sugar-free gum, sweets, and peanut butter; alcohol; and raw fish or raw meat that has not been handled safely. Lilies are also highly toxic to cats — even the pollen — so keep lilies out of a house with a cat. If your cat eats any of these, call your vet or an animal poison line straight away — do not wait for symptoms and do not try to treat it at home. Keep a note of what was eaten, how much, and when, because the vet will ask.
An adult cat is less vulnerable than a kitten to the same hazards, because its body is larger and its organs are fully developed — but the hazards are the same, and the rule is the same: if you are unsure whether a food is safe, do not give it, and ask your vet. Keep the diet simple, consistent, and measured, and keep anything the cat should not eat out of reach — including the kitchen bin, which a determined cat can still raid, and houseplants, some of which are toxic to cats. The cat food calculator works out daily calories by weight and life stage for any adult cat, and the adult cat weight calculator guide explains how to check whether the amount you are feeding is keeping weight where it should be.
For related reading, see the adult cat age calculator guide, the adult cat weight calculator guide, the cat food calculator, the kitten cat food calculator guide, the senior cat food calculator guide, the cat age in human years chart.
Frequently asked questions
How much food should an adult cat eat per day?
A typical neutered indoor adult cat of 4 kg needs about 240 calories a day, which is roughly 70 g of a typical dry food at 350 kcal per 100 g. A 3 kg cat needs about 190 calories, and a 6 kg cat about 320. Active, outdoor, or intact cats need more, and seniors a little less — adjust by body condition and your vet's advice.
How many times a day should I feed an adult cat?
Two meals a day, morning and evening, is right for most adult cats, or the same daily amount in a puzzle feeder. Kittens need three to four meals a day until about six months, then two. Free-feeding — leaving food down all day — makes portion control and appetite monitoring much harder.
Should I switch from kitten food to adult food at 12 months?
Usually yes, but ask your vet — large breeds such as Maine Coons can take 2 to 4 years to finish growing and may need kitten food for longer. Switch gradually over a week, mixing the old and new food in increasing proportions, and cut the amount to the adult factor of about 1.2 at the same time.
How do I know if my adult cat is overweight?
Feel the ribs: you should feel them easily under a thin layer of fat without pressing hard. Look from above for a visible waist behind the ribs, and from the side for a tummy tuck. If you cannot feel the ribs or there is no waist, the cat is probably overweight — cut food by about 10%, keep treats under 10% of daily calories, and ask your vet to set a target weight.
Can an adult cat drink milk?
Most adult cats cannot digest lactose well, so milk often causes an upset stomach and adds calories the cat does not need. Fresh water is what a cat needs — offer it in a clean bowl, away from the litter tray, and consider a water fountain if your cat prefers running water.
What foods are toxic to an adult cat?
Onions and garlic, chocolate, grapes and raisins, xylitol, alcohol, and lilies — even lily pollen — are all dangerous for cats. If your cat eats any of them, call your vet or an animal poison line immediately and tell them what was eaten, how much, and when.
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.