🐟 Enter Your Cat's Details

Vet formula: Uses the feline RER formula - 70 × (weight in kg)^0.75 - multiplied by feline-specific life stage factors. Cats have unique nutritional needs as obligate carnivores. Always verify with your vet for kittens, pregnant/nursing cats, or cats with health conditions.
️ Important: Never drastically restrict a cat's food. Cats that stop eating for even 2–3 days are at risk of hepatic lipidosis (fatty liver disease) - a serious, potentially fatal condition. Any weight loss plan must be gradual and vet-supervised.
Cat Details
🥣 Food Details

⚖️ Cat Weight Loss & Gain Calculator

️ Critical warning: Cats must NEVER be put on crash diets. Restricting food too aggressively causes hepatic lipidosis (fatty liver disease) - fat mobilises faster than the liver can process, leading to liver failure. Safe weight loss for cats: no more than 1–2% of body weight per week. Always consult your vet.

🥣 Cat Food Types - Calories & Feeding Guide

Food Type Type Typical kcal Moisture % Notes
Premium dry kibbleDry350–420 kcal/cup~10%Convenient; low moisture is concern
Standard dry kibbleDry290–350 kcal/cup~10%Check protein source - avoid plant-heavy
Wet pâté (premium)Wet90–120 kcal/100g70–80%Closest to natural prey moisture content
Wet chunks in gravyWet60–90 kcal/100g80–85%Lower calorie density - good for weight loss
Wet food (standard)Wet75–100 kcal/100g70–80%Good hydration support
Raw - whole preyRaw130–200 kcal/100g65–75%Closest to ancestral diet; requires balance
Raw - minced/commercialRaw110–160 kcal/100g65–75%Check taurine supplementation
Mixed dry + wetMixedVariesMixedPopular compromise; calculate each portion
Prescription / renal dietWetVaries70–80%Vet prescribed - follow label exactly

️ Cats are obligate carnivores. They require taurine, arachidonic acid, and preformed vitamin A from animal sources - nutrients they cannot synthesise from plant sources. Ensure any food or homemade diet meets these feline-specific requirements.

How Cat Food Portions Are Calculated

Step 1 - Resting Energy Requirement (RER)

RER (kcal/day) = 70 × (body weight in kg)^0.75 Feline examples: 2 kg cat: 70 × 2^0.75 = 70 × 1.68 = 118 kcal/day 4 kg cat: 70 × 4^0.75 = 70 × 2.83 = 198 kcal/day 5 kg cat: 70 × 5^0.75 = 70 × 3.34 = 234 kcal/day 7 kg cat: 70 × 7^0.75 = 70 × 4.30 = 301 kcal/day 10 kg cat: 70 × 10^0.75 = 70 × 5.62 = 394 kcal/day RER = calories needed for basic body functions at rest (breathing, circulation, organ function)

Step 2 - Feline Life Stage Factors (MER)

MER = RER × Life Stage Factor Feline-specific factors: Kitten under 4 months: RER × 2.5 Kitten 4–12 months: RER × 2.0 Neutered indoor adult: RER × 1.2 Intact adult: RER × 1.4 Active / outdoor adult: RER × 1.6 Senior cat (11+ years): RER × 1.1 Pregnant cat: RER × 2.0 Nursing cat: RER × 2.75 BCS Adjustments: BCS 1–2 (very thin): MER × 1.2 BCS 3 (thin): MER × 1.1 BCS 4–5 (ideal): MER × 1.0 BCS 6 (slightly over): MER × 0.9 BCS 7–8 (overweight): MER × 0.8 BCS 9 (obese): MER × 0.7

Step 3 - Convert kcal to Food Quantity

Daily portion = Total kcal ÷ kcal per cup (or per 100g) Example: 4 kg neutered indoor cat RER = 70 × 4^0.75 = 198 kcal MER = 198 × 1.2 = 238 kcal/day Dry kibble at 350 kcal/cup: Daily cups = 238 ÷ 350 = 0.68 cups/day Wet food at 95 kcal/100g: Daily grams = 238 ÷ 0.95 = 251g/day Split into 2–3 meals for best results.

Why Cats Need Wet Food - The Hydration Science

Cats evolved as desert predators with a LOW thirst drive. They are designed to get most moisture from prey (~70% water). Dry food: ~10% moisture Wet food: ~70–80% moisture matches prey content Raw food: ~65–75% moisture Chronically low moisture intake contributes to: - Urinary tract disease (FLUTD, crystals, blockages) - Chronic kidney disease (CKD) - #1 killer of older cats - Constipation and digestive issues Even if a cat drinks from a bowl, total daily water intake on dry food is typically 50% lower than on wet.

Frequently Asked Questions

Use the RER formula: 70 × (weight in kg)^0.75, then multiply by a feline life stage factor. A 4 kg neutered indoor cat: RER = 70 × 4^0.75 = 198 kcal. Factor 1.2 = 238 kcal/day. With 350 kcal/cup dry kibble: approximately 0.68 cups/day. With wet food at 95 kcal/100g: approximately 250g/day. Bag guidelines are averages - the calculated result is more accurate. Always recheck after 4 weeks by weighing your cat.
Veterinary nutritionists generally recommend wet food as the primary diet for cats. Cats are obligate carnivores with a low thirst drive - they evolved to get most moisture from prey (65–75% water). Dry food at 10% moisture leads to chronic mild dehydration, contributing to urinary tract disease and chronic kidney disease (CKD) - the leading cause of death in senior cats. A practical compromise: wet food as the primary diet (70%+ of calories) with a small dry component for dental benefit.
Hepatic lipidosis (fatty liver disease) occurs when a cat stops eating or dramatically reduces intake. The body mobilises fat for energy, but the feline liver cannot process the influx fast enough. Fat accumulates in liver cells, causing progressive liver failure. Even 2–3 days of significantly reduced eating can trigger it in overweight cats. It is the most common serious liver disease in cats and can be fatal without intensive veterinary treatment. This is why cat food should never be drastically restricted - any weight loss programme must be slow and vet-supervised.
Taurine is an amino acid essential for cats that they cannot synthesise in adequate quantities. Unlike dogs and humans, cats have limited ability to make taurine from other amino acids and must consume it preformed from animal tissue. Taurine deficiency causes: dilated cardiomyopathy (enlarged, weakened heart), central retinal degeneration (progressive blindness), and reproductive failure in breeding cats. All commercial cat foods (AAFCO-certified) must contain adequate taurine. Homemade diets and raw diets need careful supplementation. Never feed a dog food to a cat - it does not contain sufficient taurine.
Kittens under 4 months: 3–4 meals per day (high energy needs, small stomach). Kittens 4–12 months: 2–3 meals. Adult cats: 2–3 meals per day is ideal. Cats naturally prefer multiple small meals - they evolved making many small kills daily. Wet food must be served fresh as it spoils within 2–4 hours. Avoid free-feeding wet food. Dry food can be measured and left available, but free-feeding makes portion control impossible and contributes heavily to feline obesity.
Decide the caloric split: e.g., 40% calories from dry, 60% from wet. Total daily kcal for your cat = 280 kcal. Dry: 40% × 280 = 112 kcal. At 350 kcal/cup: 112 ÷ 350 = 0.32 cups dry. Wet: 60% × 280 = 168 kcal. At 95 kcal/100g: 168 ÷ 0.95 = 177g wet. Total: 0.32 cups dry + 177g wet. Always recalculate if you change brands, as kcal per cup/100g varies significantly between products.
Neutering reduces sex hormone levels (oestrogen and testosterone), which lowers resting metabolic rate significantly - typically 20–30% in cats. A neutered indoor adult cat needs only about 1.2× RER, compared to 1.4× for an intact adult. Many owners continue the same pre-neuter food portions after the procedure, leading to rapid weight gain. The first month after neutering is when adjustment is most important. Indoor-only lifestyle compounds this - less activity means even lower caloric needs. Always recalculate portions promptly after neutering.
Cats can survive on dry food, but veterinary consensus increasingly favours wet food as the primary diet due to the hydration issue. If your cat refuses wet food, try warming it slightly (to enhance aroma), mixing a tiny amount of wet food into dry and gradually increasing the ratio, offering different brands or textures (pâté vs chunks vs loaf), or using a cat drinking fountain (moving water encourages drinking and partially compensates for dry food's low moisture). Some cats genuinely prefer dry - in that case, ensure they drink adequate water and monitor for urinary symptoms.

Cat Food Calculator - How Much Should You Really Feed Your Cat Each Day?

Feeding a cat the correct daily amount is more nuanced than most owners realise, and the consequences of getting it wrong run in both directions. Overfeeding is the more common problem - more than fifty percent of pet cats in developed countries are overweight or obese, and the primary driver is not food quality but portion size. Underfeeding is less common but carries a uniquely serious risk for cats that does not apply to dogs: hepatic lipidosis, or fatty liver disease, which can develop within two to three days of a cat significantly reducing food intake. This is why cat portion calculation deserves careful, species-specific attention rather than simple approximation.

The feeding guidelines on cat food packaging suffer from the same limitations as dog food guidelines: they are calculated for averages, they tend toward generosity, and they cannot account for whether your cat is neutered (needs significantly fewer calories), highly active, geriatric, or managing a health condition. A neutered indoor cat has a metabolic rate approximately thirty percent lower than an intact cat of the same size - yet the bag label does not distinguish between these cats. The RER formula adjusted for feline life stage factors produces a personalised starting point that is far more accurate than the printed guidelines.

Quick example: A 5 kg neutered indoor adult cat. RER = 70 × 5^0.75 = 70 × 3.34 = 234 kcal/day. Neutered indoor factor = 1.2. Daily need = 234 × 1.2 = 281 kcal/day. With 350 kcal/cup dry kibble: 0.8 cups/day (split into 2–3 meals). With wet food at 95 kcal/100g: 296g/day. The bag might say "up to 1 cup for a 5kg cat" - the calculated result helps you use the right portion of that range.

Why Cats Need Wet Food - The Obligate Carnivore and Hydration Problem

Cats are obligate carnivores - a biological classification that goes beyond dietary preference. Unlike dogs, who are omnivores capable of extracting nutrition from plant sources, cats have several metabolic pathways that simply do not function without animal-derived nutrients. They cannot synthesise taurine (essential for heart and eye health), arachidonic acid (an essential fatty acid), or preformed vitamin A from beta-carotene - all of these must come from animal tissue. Any cat food diet, whether commercial or homemade, must account for these requirements or serious deficiencies will develop.

The hydration question is equally significant. Cats evolved as desert predators with a characteristically low thirst drive - they were designed to obtain the majority of their moisture from prey, which contains approximately sixty-five to seventy percent water. Dry cat food contains only about ten percent moisture. A cat eating exclusively dry food typically consumes fifty percent less total daily water than a cat eating wet food, even if they drink from a bowl. This chronic mild dehydration is not immediately visible but contributes meaningfully to the two most common serious diseases in older cats: urinary tract disease (crystal formation, blockages, and feline idiopathic cystitis) and chronic kidney disease, which affects an estimated thirty to forty percent of cats over twelve years old.

Dry Food - Pros and Cons

  • Convenient, long shelf life after opening
  • Some dental abrasion benefit (limited evidence)
  • Easier to free-feed if needed (though not recommended)
  • Generally lower cost per calorie
  • Only ~10% moisture - low hydration
  • Higher carbohydrate content than cats need
  • Linked to higher rates of urinary disease and CKD

Wet Food - Pros and Cons

  • 70–80% moisture - closely matches prey content
  • Supports urinary tract and kidney health
  • Higher protein, lower carbohydrate profile
  • Cats generally find it more palatable
  • Ideal for weight management (lower calorie density)
  • More expensive per calorie than dry
  • Cannot be left out - spoils within 4 hours

Hepatic Lipidosis - The Critical Warning Unique to Cats

Hepatic lipidosis, commonly called fatty liver disease, is one of the most serious nutritional risks in cats and has no direct equivalent in dogs. When a cat stops eating or significantly reduces food intake - even for as little as two to three days - the body begins mobilising fat reserves for energy. In cats, the liver is unusually limited in its capacity to process this sudden influx of fatty acids. Fat accumulates in liver cells faster than the liver can metabolise it, causing the liver to become enlarged, yellow, and progressively dysfunctional. Without treatment, the condition is fatal. With aggressive veterinary intervention including feeding tube placement, it is survivable but requires weeks of intensive management.

The clinical implication is direct: never dramatically restrict a cat's food intake without veterinary guidance. Weight loss in overweight cats must be slow - the safe rate is one to two percent of body weight per week, which for a six-kilogram cat means losing sixty to one hundred twenty grams per week. Any faster and the risk of triggering hepatic lipidosis rises significantly. If a cat refuses food for more than twenty-four to forty-eight hours for any reason, veterinary attention is warranted. This is why the weight management section of this calculator is cautious by design, and why the associated warning is not alarmist but clinically necessary.

Feeding Frequency - How Many Meals Per Day for Cats?

Cats are natural grazers who, in the wild, would make multiple small kills throughout the day. Their digestive system is well suited to frequent small meals rather than one or two large ones. In practice, two to three meals per day is the standard recommendation for adult cats, with the total daily portion divided equally. Kittens under four months need three to four meals due to their small stomach capacity and high energy requirements relative to body size.

  • Kittens under 4 months: 3–4 small meals per day. Their caloric needs per kilogram of body weight are very high, and their stomachs cannot hold enough food in a single sitting. Never restrict kitten food intake - they are growing rapidly and need consistent access to calories.
  • Kittens 4–12 months: 2–3 meals per day, gradually transitioning toward the adult feeding schedule. Continue kitten formula food until twelve months for most breeds.
  • Adult cats: 2–3 meals per day is ideal. If feeding wet food, divide into two or three servings as wet food cannot be left out for more than four hours without spoiling. Dry food can be split into two meals or, if weight is not a concern, measured and left available.
  • Senior cats (11+ years): 2–3 smaller meals per day, potentially more frequent if the cat shows reduced appetite or digestive sensitivity. Senior cats with dental disease may find wet food easier to eat than kibble.
  • Avoid free-feeding wet food: Wet food left out spoils within two to four hours and can become a source of bacterial contamination. Dry food can be more safely left available, but free-feeding makes portion control impossible and is a major contributor to feline obesity.

How this calculator works, and where the numbers come from

The Cat Food Calculator applies the standard formula for this calculation to the values you enter and updates the result as you type. The calculation itself happens in your browser, and the page explains the method so you can check any result by hand.

Please note: This tool gives general estimates. Every animal is different, so it is not veterinary advice. Ask your vet before changing diet, dosing or care.

Sources and further reading

Learn more

Read our guide: The Dog Years Myth, and How Much Your Dog Should Eat

Last reviewed: by the CalcQube Editorial Team. See our editorial policy for how we build and check calculators, or report an error.