How much food should a senior dog eat? Less than it used to — but not much less, and not less of everything. A senior dog 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 dog food calculator in words: the calorie tables for senior dogs by weight, how to work out portions in cups and grams, what changes at each stage of the senior years, the mistakes that most often lead to an overweight or underweight older dog, and the foods a senior dog should never eat. It uses the resting energy requirement (RER) formula vets use, with the lower activity factors that suit older dogs.
The senior years are when feeding mistakes show up most clearly, in both directions. A dog 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. A dog 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 dog 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 dog.
How many calories does a senior dog need?
Veterinary nutritionists start with the resting energy requirement, or RER — the calories a dog 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 1.6 for a typical neutered adult, but about 1.2 to 1.4 for a senior or a dog that needs to lose weight. So a senior dog of 20 kg has an RER of about 330 calories, and at the 1.3 factor it needs about 430 calories a day — against about 530 for the same dog as a young neutered adult. That difference, about 20%, is the whole of the senior adjustment: 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 dog that is still active — long daily walks, play, training — needs more than one that sleeps most of the day, and a dog 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 dog 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 dog is always worth checking, and it is not solved by simply feeding more.
Senior dog daily calories by weight
Use the table below to find your senior dog's daily calories. Find the row nearest the dog's weight, then pick the column that matches the dog: the middle column is the usual starting point for a senior dog, the right-hand column is for a very quiet senior or one that needs to lose weight, and the left-hand column shows what the same dog needed as a young adult, so you can see how much has changed.
| Body weight | Young neutered adult (×1.6) | Senior dog (×1.3) | Quiet senior / weight loss (×1.2) |
|---|---|---|---|
| 5 kg | 375 | 305 | 280 |
| 10 kg | 630 | 510 | 470 |
| 20 kg | 1060 | 860 | 795 |
| 30 kg | 1435 | 1165 | 1075 |
| 50 kg | 2105 | 1710 | 1580 |
If your dog is between two rows, take the lower figure first: it is easier to add food to a dog that is losing weight than to take weight off a dog that has gained it, and senior dogs gain weight easily when food is guessed rather than measured. Note that calories are the real target and cups are only a translation — different foods have very different calorie densities, so always check the kcal per cup or per 100 g on your own bag or tin and work from that. The cups figures below assume a typical dry food at around 350 kcal per cup, a common figure, but your food may differ by a wide margin, and the bag's number always wins over this guide's.
How much food in cups and grams per day
For a senior dog of 20 kg needing about 430 calories a day, that is roughly 1.2 cups or about 125 g of a typical dry food at 350 kcal per cup. For a senior dog of 10 kg needing about 265 calories, it is roughly 0.8 cups or about 75 g. For a senior dog of 30 kg needing about 590 calories, it is roughly 1.7 cups or about 170 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 dog's digestion is less forgiving than a young dog's. 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 20 kg senior dog needing 430 calories would need roughly 500 g of wet food a day, split across meals.
Measure food with scales or a measuring cup, not a mug or a handful. A cup in one house can be half as much again as a cup in another, and that hidden extra is often the whole reason a senior dog is overweight. Weigh the daily amount once, note what it looks like in your cup, and use that cup every time. Treats count too: they should stay under 10% of daily calories, which for a 20 kg senior dog is under about 45 calories of treats a day — a few small training treats, not a handful of biscuits. Soft treats are often better for a senior dog with worn teeth, and treats that need hard chewing can be a choking risk for a dog with dental problems, so choose them with your dog's mouth in mind.
Feeding a senior dog by stage
The early senior years — from the senior boundary to about two years past it — are usually the easiest to feed. The dog 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 1.6 to the senior factor of about 1.2 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 dogs need protein to hold muscle, and a food that cuts protein to cut calories is the wrong trade.
The late senior years — the last few years of life — need more attention. Appetite can fall, teeth can hurt, and the dog may eat slowly or leave food. Warm the food slightly to release smell, offer smaller meals more often, and raise the bowl so the dog does not have to bend a stiff neck to eat. Some seniors develop kidney or other health issues that change the diet entirely — lower phosphorus, controlled protein, 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 dogs may be prone to dental disease and joint problems, 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 dogs
The most common mistake is not changing the amount at all: the dog 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 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 dog slim, and watching it lose muscle instead of fat. Muscle and fat are not the same thing, and a senior dog 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 down all day — which makes it impossible to know how much the dog has eaten and hides appetite changes that are often the first sign of illness in a senior dog. The fourth is treat creep: a biscuit here, a piece of cheese there, and the dog's daily calories rise by a quarter without anyone noticing. The fifth is switching foods suddenly, which upsets a senior dog's digestion more than a young dog's — change foods gradually over a week, mixing the old and new in increasing proportions. The sixth is table scraps, which are often fatty, salty, or simply too many calories, and which teach begging. The senior dog diet guide covers the same ground in more detail, and the senior dog weight calculator guide explains how to set a target weight for an older dog.
Foods a senior dog should never eat
Some everyday foods are toxic to dogs of any age and should never be given, in any amount: chocolate, cocoa, and coffee; grapes and raisins; onions, garlic, leeks, and chives; xylitol, also called birch sugar, found in some sugar-free gum, sweets, and peanut butter; macadamia nuts; alcohol; and cooked bones, which can splinter. Raw dough, mouldy food, and very fatty scraps are also dangerous. If your senior dog 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 dog is more vulnerable than a young dog to the same hazards, because its kidneys, liver, and digestion are less able to cope with a shock. Fatty scraps that a young dog might shrug off can trigger pancreatitis in an older dog, and a bout of vomiting or diarrhoea that a young dog recovers from in a day can leave a senior dog dehydrated and weak. Keep the diet simple, consistent, and measured, and keep anything the dog should not eat out of reach — including the kitchen bin, which a determined older dog 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 dog diet guide, the senior dog weight calculator guide, the senior dog age calculator guide, the dog food calculator, the senior dog lifespan guide, the dog ideal weight calculator.
Frequently asked questions
How much food should a senior dog eat per day?
A senior dog of 20 kg needs about 430 calories a day at the usual senior factor of 1.3 — roughly 1.2 cups or about 125 g of a typical dry food at 350 kcal per cup. A 10 kg senior needs about 265 calories, and a 30 kg senior about 590. Adjust by body condition and your vet's advice — active seniors need more, and quiet ones less.
Should I switch my dog 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 the senior boundary. 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 dog has a health condition, ask your vet before choosing a special diet.
How many times a day should I feed a senior dog?
Two meals a day, morning and evening, is right for most senior dogs. In the late senior years, smaller meals more often — three small meals, or two meals with a small midday snack — can suit a dog 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 dog losing weight?
Unexplained weight loss in a senior dog is always worth checking with a vet — it can be caused by dental pain, kidney or other organ 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 dog 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 dogs and people in the house. The raw food calculator gives portion guidance, but it does not replace veterinary advice, especially for seniors or dogs with health conditions.
What foods are toxic to a senior dog?
Chocolate, grapes and raisins, onions and garlic, xylitol, macadamia nuts, alcohol, and cooked bones are all dangerous for dogs of any age. If your senior dog 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.