How Much Should You Feed Your Cat?
The single biggest cause of feline obesity is the bag label. Most pet food bags suggest portions in a wide range that assumes an active, intact cat, yet roughly 60% of house cats are spayed or neutered indoor adults who need far less. This calculator skips the guesswork and uses the same energy math your veterinarian uses, then translates the calorie target into real cans and cups based on the exact food in your pantry.
The Vet Formula Behind the Numbers
Daily energy starts with Resting Energy Requirement (RER), the calories a cat burns just existing. We then multiply by a maintenance factor for life stage and a body-condition adjustment. A 10 lb (4.5 kg) ideal-weight indoor adult lands near 200 kcal a day, which is only about two 95-kcal cans or roughly half a cup of typical 350-kcal dry food.
RER = 70 x (weight_kg ^ 0.75) | Daily kcal = RER x life-stage x condition
Why Wet and Dry Split Matters
Wet food is mostly water, so it delivers fewer calories per gram and helps with hydration and urinary health, while dry food is calorie-dense and convenient. Feeding a 50/50 split by calories means you cannot simply give half a can and half a cup; you have to balance the energy. The calculator does that division for you, so a cat eating 60% wet still hits the same total target without overshooting.
Frequently Asked Questions
Is this for wet food, dry food, or both?
Both. You enter the calories per can and per cup of the foods you actually use, then choose what percentage of the diet should come from wet food. The calculator splits the daily calorie target between the two and tells you how many cans and cups that works out to.
Why does my cat need fewer calories than the bag says?
Bag guidelines are generous and assume an active, often unneutered cat. A spayed or neutered indoor cat can need 20 to 30 percent fewer calories, which is why so many house cats slowly gain weight on label portions. Calculating from body weight and condition gives a far more accurate starting point.
How fast should an overweight cat lose weight?
Slowly and under veterinary guidance. Cats should lose no more than about 0.5 to 2 percent of body weight per week, because rapid weight loss in cats can trigger a dangerous liver condition called hepatic lipidosis. Use the overweight setting as a starting ration and have your vet confirm the plan.
How often should I recheck the portion?
Weigh your cat about once a month, ideally on the same scale at the same time of day. If you can no longer easily feel the ribs or the waist disappears, trim the daily amount by roughly 10 percent and recheck in a few weeks. Kittens and seniors should be reassessed more often as their needs change.
Practical Guide for Cat Food Portion Calculator
Calorie counts are the honest currency of feeding, not cups or cans. Two dry foods can differ by more than 100 kcal per cup, and a premium pate can hold twice the calories of a watery shred in the same size can. Always read the kcal/can and kcal/cup off the package or the brand website and plug those exact numbers in, because a guessed density can throw your portion off by a third.
Body condition score beats the bathroom scale for accuracy. Run your hands over your cat: you should feel the ribs under a thin fat layer, see a tucked waist from above, and notice a slight belly tuck from the side. If the ribs are buried, set the calculator to overweight; if they jut out sharply, choose underweight. The number on the scale only tells you how to track progress over time.
Split the daily total across at least two meals, and more for kittens. Cats are grazers by nature, so 3 to 4 small meals suits growing kittens and cats prone to vomiting after fast eating. If you free-feed dry food, measure the full day's allowance into the bowl in the morning rather than topping it up, so the bag is not silently doubling the portion.
Quick Checklist
- Look up the exact kcal per can and kcal per cup for your foods.
- Do a hands-on rib and waist check to set the body condition.
- Weigh your cat monthly and adjust the ration by about 10% if it drifts.
- Divide the daily amount into 2 to 4 measured meals, never free-pour.