How much food should a senior cat eat? Less than it used to — but not much less, and not less of everything. A senior cat moves less than a young adult, so it burns fewer calories, but it still needs good protein to hold its muscle, and it still needs a complete, balanced diet. This guide is the senior cat food calculator in words: the calorie tables for senior cats by weight, how to work out portions in grams, what changes at each stage of the senior years, the mistakes that most often lead to an overweight or underweight older cat, and the foods a senior cat should never eat. It uses the resting energy requirement (RER) formula vets use, with the lower activity factors that suit older cats.
The senior years are when feeding mistakes show up most clearly, in both directions. A cat that has eaten the same amount since it was two will slowly gain weight as its activity falls, and that extra weight strains joints that are already stiffening and raises the risk of diabetes. A cat that loses its appetite, or whose owner cuts food too hard in the hope of keeping it slim, will lose muscle fast — and muscle lost in old age is very hard to win back. The right amount is the one that keeps weight steady and muscle held: weigh the cat monthly, feel the ribs, and adjust food by about 10% at a time rather than changing everything at once. This guide gives the numbers to start from, and your vet fine-tunes them for your individual cat.
How many calories does a senior 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, but about 1.1 to 1.4 for a senior. So a senior cat of 4 kg has an RER of about 200 calories, and at the 1.1 factor it needs about 220 calories a day — against about 240 for the same cat as a young neutered adult. That difference, about 10%, is the whole of the senior adjustment for a quiet senior: it is real, but it is not a starvation diet, and cutting further than that risks muscle loss.
These factors are the standard ones used in veterinary nutrition, but they are still starting points. A senior cat that is still active — long daily play sessions, climbing, patrolling a garden — needs more than one that sleeps most of the day, and a cat with a health condition may need a different diet entirely, which is a vet decision, not a food-brand decision. 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 a senior cat is always worth checking, and it is not solved by simply feeding more.
Senior cat daily calories by weight
Use the table below to find your senior cat's daily calories. Find the row nearest the cat's weight, then pick the column that matches the cat: the middle column is the usual starting point for a senior cat, the right-hand column is for a senior that needs to lose weight, and the left-hand column shows what the same cat needed as a young adult, so you can see how much has changed.
| Body weight | Young neutered adult (×1.2) | Senior cat (×1.1) | Weight loss (×0.9) |
|---|---|---|---|
| 2 kg | 140 | 130 | 105 |
| 3 kg | 190 | 175 | 145 |
| 4 kg | 240 | 220 | 180 |
| 5 kg | 280 | 255 | 210 |
| 6 kg | 320 | 295 | 240 |
| 8 kg | 400 | 365 | 300 |
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 senior cats gain weight easily when food is guessed rather than measured. 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 by a wide margin, and the packet's number always wins over this guide's.
How much food in grams per day
For a senior cat of 4 kg needing about 220 calories a day, that is roughly 65 g of a typical dry food at 350 kcal per 100 g. For a senior cat of 3 kg needing about 175 calories, it is roughly 50 g. For a senior cat of 6 kg needing about 295 calories, it is roughly 85 g. Split the daily amount into two meals — morning and evening — rather than one large meal: two smaller meals are easier on digestion, and a senior cat's digestion is less forgiving than a young cat's. In the late senior years, smaller meals more often — three small meals, or two meals with a small midday snack — can suit a cat that eats slowly or leaves food. 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 senior cat needing 220 calories would need roughly 260 g of wet food a day, split across meals.
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 a senior cat is overweight. Weigh the daily amount once, note what it looks like in your scoop, and use that scoop every time. Treats count too: they should stay under 10% of daily calories, which for a 4 kg senior cat is under about 20 calories of treats a day — a few small treats, not a handful. Soft treats are often better for a senior cat with worn teeth, and treats that need hard chewing can be a problem for a cat with dental disease, so choose them with your cat's mouth in mind. Fresh water should always be available, in several places — senior cats often drink more from a fountain or a bowl away from their food — because good hydration supports kidney health.
Feeding a senior cat by stage
The early senior years — from about 11 to about 14 — are usually the easiest to feed. The cat is slowing down but still active, its teeth are mostly sound, and its appetite is steady. The main change is the calorie cut: move from the adult factor of about 1.2 to the senior factor of about 1.1 to 1.4, weigh monthly, and adjust by 10% at a time. A senior food, or an adult food fed in a smaller amount with your vet's agreement, is usually right at this stage. Keep protein good — older cats need protein to hold muscle, and a food that cuts protein to cut calories is the wrong trade.
The geriatric years — from 15 on — need more attention. Appetite can fall, teeth can hurt, and the cat may eat slowly or leave food. Warm the food slightly to release smell, offer smaller meals more often, and put the bowl where the cat can reach it easily, without stairs or a high-sided tray in the way. Some seniors develop kidney or other health issues that change the diet entirely — controlled phosphorus, or a prescription diet — which is a vet decision, not a food-brand decision, and therapeutic diets are medicines in food form and should not be chosen by guesswork. Senior cats may be prone to kidney disease, thyroid problems, and dental disease, so mention any change in appetite, thirst, or weight to your vet promptly rather than adjusting food on your own.
Common feeding mistakes with senior cats
The most common mistake is not changing the amount at all: the cat eats what it ate at two years old, its activity falls by a third, and its weight creeps up year by year until its joints and its blood sugar are carrying far more than they were built for. The second is the opposite mistake — cutting food too hard in the hope of keeping the cat slim, and watching it lose muscle instead of fat. Muscle and fat are not the same thing, and a senior cat that is thin but weak is in worse shape than one that is a little heavy but strong. Weigh monthly, feel the ribs and the muscles over the spine and hips, and aim for steady weight with muscle held, not for the lowest number on the scales.
The third mistake is free-feeding — leaving a full bowl of dry food down all day — which makes it impossible to know how much the cat has eaten and hides appetite changes that are often the first sign of illness in a senior cat. The fourth 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 fifth is switching foods suddenly, which upsets a senior cat's digestion more than a young cat's — change foods gradually over a week, mixing the old and new in increasing proportions. The sixth is milk: most adult cats cannot digest lactose well, and milk adds calories the cat does not need. The adult cat food calculator guide covers the same ground for younger cats, and the senior cat weight calculator guide explains how to set a target weight for an older cat.
Foods a senior cat should never eat
Some everyday foods are toxic to cats of any age 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 senior 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.
A senior cat is more vulnerable than a young cat to the same hazards, because its kidneys, liver, and digestion are less able to cope with a shock. A small amount of a toxic food that a young cat might survive can be serious for a senior cat, and a bout of vomiting or diarrhoea that a young cat recovers from in a day can leave a senior cat dehydrated and weak. 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 older cat can still raid. If you are unsure whether a food is safe, do not give it, and ask your vet.
For related reading, see the senior cat age calculator guide, the senior cat weight calculator guide, the adult cat food calculator guide, the cat food calculator, the senior cat lifespan guide, the cat ideal weight calculator.
Frequently asked questions
How much food should a senior cat eat per day?
A senior cat of 4 kg needs about 220 calories a day at the usual senior factor of 1.1 — roughly 65 g of a typical dry food at 350 kcal per 100 g. A 3 kg senior needs about 175 calories, and a 6 kg senior about 295. Adjust by body condition and your vet's advice — active seniors need more, and quiet ones less.
Should I switch my cat to a senior food?
A senior food, or an adult food fed in a smaller amount with your vet's agreement, is usually right from about 11 years old. Look for a food labelled complete and balanced, with good protein to hold muscle — a food that cuts protein to cut calories is the wrong trade. If your cat has a health condition, ask your vet before choosing a special diet.
How many times a day should I feed a senior cat?
Two meals a day, morning and evening, is right for most senior cats. In the late senior years, smaller meals more often — three small meals, or two meals with a small midday snack — can suit a cat that eats slowly or leaves food. Free-feeding, leaving food down all day, makes portion control and appetite monitoring much harder.
Why is my senior cat losing weight?
Unexplained weight loss in a senior cat is always worth checking with a vet — it can be caused by dental pain, kidney or thyroid problems, or other health issues, and it is not solved by simply feeding more. Weigh monthly, note any change in appetite, thirst, or energy, and mention it to your vet promptly rather than adjusting food on your own.
Can a senior cat eat raw food?
Raw diets are possible but need care: they must be complete and balanced, handled hygienically, and agreed with your vet, because an unbalanced raw diet can cause deficiencies and raw meat carries bacteria that can affect cats and people in the house. They do not replace veterinary advice, especially for seniors or cats with health conditions.
What foods are toxic to a senior cat?
Onions and garlic, chocolate, grapes and raisins, xylitol, alcohol, and lilies — even lily pollen — are all dangerous for cats of any age. If your senior 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.