How Much Wet Food to Feed a Cat (By Weight)
Updated September 2026 · Sources: NRC energy equations, WSAVA Global Nutrition Guidelines
A typical neutered indoor cat needs about 215 kcal a day at 3.5 kg, 260 kcal at 4.5 kg and 302 kcal at 5.5 kg — which works out to roughly 2.4, 2.9 and 3.4 three-ounce cans of a typical 90 kcal wet food, or 1.4, 1.7 and 2.0 five-and-a-half-ounce cans of a 150 kcal food. Cats need far fewer calories than dogs of the same weight, so the can count is smaller than most owners expect.
Wet food is the format most veterinarians reach for when a cat needs more water — and most cats do. A cat evolved to get much of its moisture from prey, and many cats on dry food alone drink less than the roughly 40–60 ml per kg a day they need. Wet food is about 75% water, so switching or mixing changes both the calorie maths and the water balance at the same time. Here is the calorie side, worked by weight.
Daily calories by body weight and activity
Same method as everywhere else on this site: resting energy requirement from body weight, times a factor for life stage, activity and neuter status. Cat factors are not dog factors — a neutered cat uses 1.0–1.4×, where a neutered dog uses 1.4–2.5× for the same activity words.
| Cat weight | RER (kcal) | Indoor (1.0×) | Typical (1.2×) | Active (1.4×) |
|---|---|---|---|---|
| 3.5 kg (7.7 lb) | 179 | 179 kcal | 215 kcal | 251 kcal |
| 4.5 kg (9.9 lb) | 216 | 216 kcal | 260 kcal | 303 kcal |
| 5.5 kg (12.1 lb) | 251 | 251 kcal | 302 kcal | 352 kcal |
| 6.5 kg (14.3 lb) | 285 | 285 kcal | 342 kcal | 399 kcal |
"Indoor" is the strictly-inside, low-activity cat; "Typical" is the ordinary neutered house cat; "Active" covers an outdoor or very playful cat. If your cat is intact rather than neutered, the factors run one step higher (1.2 / 1.4 / 1.6). Use the cat portion calculator for your cat's exact combination.
Converting calories into cans
The calorie figure is food-independent; the cans are not. Use the kcal printed on your own can, because wet cat foods range from about 70 to 110 kcal per 3 oz — a wider spread than dry foods show.
| Cat weight | Typical daily kcal | 3 oz cans (90 kcal) | 5.5 oz cans (150 kcal) |
|---|---|---|---|
| 3.5 kg | 215 kcal | 2.4 cans | 1.4 cans |
| 4.5 kg | 260 kcal | 2.9 cans | 1.7 cans |
| 5.5 kg | 302 kcal | 3.4 cans | 2.0 cans |
| 6.5 kg | 342 kcal | 3.8 cans | 2.3 cans |
Two things to notice. First, the can counts assume a whole can is eaten — in practice half a can twice a day is the same total, and a 3 oz can split across two meals is a normal pattern. Second, a 3 oz can is only about 85 g of food, so a 5.5 kg cat on a 150 kcal food is eating roughly 310 g a day. That is normal for wet feeding; it is not a mistake in the arithmetic.
Mixing wet and dry
Most owners who feed wet food mix it with dry rather than replacing it. Do the arithmetic in calories, never in cans versus cups:
- Get the cat's total daily calories from the first table. A 4.5 kg typical cat: 260 kcal.
- Choose the split. 50/50 is a common starting point for a cat who needs more water but is used to kibble.
- Convert each half using its own food: 130 kcal of wet (about 0.9 five-and-a-half-ounce cans at 150 kcal) plus 130 kcal of dry (about 34 g at 380 kcal per 100 g).
The mistake to avoid is the one that catches most people: feeding the full dry portion and adding wet food on top. That adds calories without looking like it, and it is the usual reason a mixed-fed cat gains weight. Our wet-to-dry conversion guide covers the full method.
The part that is not about calories: water
For cats, wet food is doing a second job. Cats are descended from desert hunters and have a naturally low thirst drive; a cat on dry food may drink noticeably less than the 40–60 ml per kg a day it actually needs, and mild chronic dehydration is a recognised contributor to urinary and kidney problems in cats. See how much water a cat should drink for the intake side.
A 5.5 oz can of wet food is roughly 115 g of water. For a 5 kg cat that is a large share of its daily moisture — which is why wet food, or a wet-and-dry mix, is such a common recommendation for cats with a history of urinary issues. If your cat will not drink from a bowl, changing the food format often does more than changing the bowl.
Food safety: how long wet food can sit out
Wet food spoils faster than kibble and the rules are stricter than most owners assume:
- At room temperature: offer the meal, then lift what is left after about 30 minutes. Discard any wet food that has been out for more than 2 hours — bacteria multiply quickly in a wet, protein-rich food at room temperature.
- In the fridge: cover the unused part of an opened can and use it within 3 days. Bring it to room temperature before serving; most cats refuse food straight from the fridge.
- Do not refill on top of old food. Leftovers in the bowl are the usual cause of a cat turning its nose up at a fresh can.
Weighing rather than guessing: wet food is dense and uniform, so a scale gives a very stable reading — see the kitchen scale we use for portions, which makes half a can easy to judge exactly.
Comparing foods: check the kcal per can on the label before you stock up, because the figure varies more between wet formulas than between dry ones — browse wet cat food on Amazon.
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If your cat needs to lose weight
Overweight cats need a calorie target below their resting energy requirement, not above it — and this is the one place on this page where you should not set the amount yourself. A cat's target is roughly 0.8 × RER of the ideal weight, aiming for a loss of 0.5–2% of body weight per week. Faster than that is genuinely dangerous: cats that lose weight too quickly can develop hepatic lipidosis, a serious liver condition. Use the cat weight-loss plan for the worked method, and set the target with your veterinarian.
Frequently asked questions
How many cans of wet food should I feed my cat per day?
For a typical neutered indoor cat: about 2.4 three-ounce cans or 1.4 five-and-a-half-ounce cans at 3.5 kg, rising to 3.8 three-ounce cans or 2.3 five-and-a-half-ounce cans at 6.5 kg, assuming 90 kcal per 3 oz can and 150 kcal per 5.5 oz can. Check the kcal on your own can and use the calculator above.
Is wet food better than dry food for cats?
Not better in every respect, but it delivers far more water — roughly 75% of wet food is moisture, against about 10% for dry. That matters for cats, who have a low thirst drive and are prone to urinary and kidney problems. Wet food costs more per calorie and does not clean teeth, which is the case for the trade-off in our wet vs dry cat food comparison.
How long can wet cat food sit out?
Lift the bowl after about 30 minutes and discard anything that has been at room temperature for more than 2 hours. Cover and refrigerate the unused part of an opened can and use it within 3 days, bringing it to room temperature before serving.
Can I mix wet and dry food for my cat?
Yes, and it is a common approach. Split the cat's total daily calories between the two foods, then convert each share using its own calorie content. Feeding the full dry portion and adding wet food on top is the mistake to avoid — it adds calories without appearing to.
Source
Energy calculations follow the National Research Council's energy equations for cats (RER = 70 × kg0.75, times a life-stage, activity and neuter factor), as implemented in this site's calculator and the cat portion calculator. Can values assume 90 kcal per 3 oz can and 150 kcal per 5.5 oz can; the hydration and weight-loss figures follow the WSAVA Global Nutrition Guidelines and standard feline practice. This page is general information, not veterinary medical advice — set a weight-loss target with your veterinarian.
Related on this site: cat portion calculator · wet vs dry cat food · how much water a cat should drink · cat weight-loss plan · cat body condition score