Kittens grow fast, and their food needs change almost every month. A tiny eight week old kitten needs far more energy per kilogram than an adult cat, because it is building bones, muscles, and a brain all at once. This free calculator works out daily grams by age and weight, split across three or four small meals.
Growth is the reason kittens eat so much. The calculator multiplies resting energy by a growth factor: two and a half for very young kittens under nine weeks, two for kittens up to twenty weeks, and one point eight for older kittens approaching a year. That factor falls as growth slows, which is why the portion must be rechecked monthly.
Age in weeks matters more than age in months, because a four week gap at this stage is a large share of a kitten's life. Enter the age in weeks as exactly as you know it, from breeder papers, shelter records, or your vet. If you only know an approximate age, use the vet's estimate and recheck at the next visit.
Weight is the second key number. Weigh your kitten weekly on kitchen scales, in a bowl, and note the number. A healthy kitten gains steadily, often fifty to one hundred grams a week in early months. A kitten that stops gaining, or loses weight, needs a vet check promptly, because small bodies have little reserve.
Meal frequency protects small stomachs. Young kittens do best on four meals a day, spread from morning to evening. Older kittens, past about six months, manage well on three meals. The calculator gives you the meal count and the grams per meal, so you never have to divide the daily total yourself.
Kitten food is different from adult food. It carries more protein, more fat, and more calories per gram, plus nutrients for brain and eye development. Feed a food labelled complete for kittens, and keep the kitten on it until around twelve months, or until your vet advises a switch to adult food.
Wet and dry food can mix, as long as the total grams match the daily target. If you feed half wet and half dry, convert each part by its own energy value, because wet food carries far fewer calories per gram. Many owners find a mix suits kittens best: wet food for hydration and smell, dry food for grazing and teeth.
Fresh water matters from day one. Place a water bowl away from the food bowl, because cats often prefer to drink away from their food. Change the water daily, and wash the bowl often. A kitten that eats dry food especially needs easy access to fresh water all day.
Watch the body, not just the numbers. You should feel ribs under a thin fat cover, but not see them sharply. A round, tight belly after meals is normal in kittens, but a constantly bloated belly, diarrhoea, or vomiting needs vet advice. Numbers guide you, but your kitten's body confirms the plan.
Transition to adult food slowly at around a year old. Mix adult food into kitten food over seven to ten days, increasing the adult share daily. A sudden switch upsets the stomach and can cause diarrhoea, which is the last thing a growing kitten needs.
Use the calculator above with your kitten's current age and weight, and repeat it monthly. A growing kitten deserves food that grows with it, and a minute of maths each month keeps meals right through the fastest year of its life.
A final note for new kitten owners: keep a simple growth diary with the weekly weight, the daily grams fed, and any vet advice, all in one notebook or phone note. That diary becomes gold at vet visits, because the vet can see growth at a glance instead of guessing from memory. It also helps you spot problems early, since a kitten that stops gaining for two weeks in a row deserves attention before the next routine visit.