How many calories does a cat need per day?

A typical neutered adult indoor cat weighing 4 kg needs approximately 180–200 kcal/day. Using the veterinary RER formula (70 × body weight kg^0.75 × 1.0 for neutered indoor adult): a 3 kg cat needs ~140 kcal/day, a 4.5 kg cat ~210 kcal/day, a 6 kg cat ~265 kcal/day. Outdoor, intact, or highly active cats need 20–40% more. Most commercial cat pouches contain 80–100 kcal, so a 4 kg indoor cat needs around 2 pouches daily — not three, as most owners assume.

Why do indoor cats need fewer calories than outdoor cats?

Indoor cats expend significantly less energy because they lack the activity of hunting, territory patrol, and environmental thermoregulation. An outdoor cat can burn 30–50% more calories per day than a sedentary indoor companion of the same weight. Most commercial cat food guidelines are calibrated for an average cat — not the typical neutered indoor house cat — which is why indoor cats gain weight so easily on standard portions.

How many calories does a kitten need per day?

Kittens need approximately 2–2.5× the RER of an adult cat of the same weight to fuel rapid growth, skeletal development, and high activity. A 1 kg kitten needs roughly 200 kcal/day; a 2 kg kitten around 330 kcal/day. Kittens should be fed kitten-formula food (higher protein, DHA, calcium) until 12 months. After neutering at around 5–6 months, reduce portions by 15–20% to account for the metabolic shift.

How can I tell if my cat is overweight?

Use the WSAVA 9-point Body Condition Score (BCS). At ideal weight (BCS 4–5): you can feel ribs easily with gentle pressure but not see them; there is a visible waist narrowing behind the ribs when viewed from above; and a slight abdominal tuck from the side. If ribs are difficult to feel and the waist is absent or the belly hangs low, your cat is likely overweight (BCS 6–9). Around 60% of pet cats in the US are overweight or obese.

How should I adjust a cat's calories after spaying or neutering?

Reduce daily calories by 15–25% within the first 2 weeks post-surgery. Neutering and spaying lower resting metabolic rate by removing sex hormone influence on energy expenditure. This shift is permanent — the same portions that kept your cat lean before surgery will cause gradual weight gain afterward. Most veterinary nutrition guidelines recommend an immediate post-neuter diet review rather than waiting until weight is already gained.

Is wet food or dry food better for a cat's calorie intake?

Neither is inherently better, but caloric density differs significantly. Dry cat food typically contains 300–450 kcal per 100g, while wet food contains 60–120 kcal per 100g (due to high water content). This means a small volume of dry food can contain twice the calories of a full pouch of wet food. Mixed feeding (some wet, some dry) is common; the DIY Farmer calculator supports split feeding plans to help you balance both types accurately.

Cat Calorie Calculator — Free Vet RER Formula | Daily kcal & Portions

Name: Cat Calorie Calculator
Availability: InStock
Rating: 4.8 (893 reviews)
Author: Dr. Marcus Whitfield

1 · How much does your cat weigh?

A typical healthy adult cat weighs 3.5–5.5 kg (8–12 lb). Use a recent scale reading.

2 · Body condition score (BCS)

Pick the silhouette that looks most like your cat from above. Need help?

BCS: 5 Ideal

3 · Spay/neuter status

Spayed / Neutered Intact

4 · Life stage

Kitten (under 1 yr) Adult Senior (11+ yr)

5 · Lifestyle

Indoor (typical) Outdoor / very active

6 · Food calories (optional)

Check the label — for cat food, kcal per can or per cup are most common.

7 · Include treat allotment?

If included, 10% of daily calories are reserved for treats.

Include 10% treats Exclude treats

8 · Cat's name (optional)

💡 In the print dialog, choose "Save as PDF" to download your personalised feeding plan.

Awaiting your cat's details
Enter weight to see your personalised feeding plan instantly.

How it works

The formula behind your cat's number

Step 1 — Resting Energy Requirement (RER): 70 × (weight in kg)^0.75.

Step 2 — Multiplier: A typical neutered indoor cat needs about 1.2× RER — much less than a dog. Intact adults: 1.4×. Active or outdoor cats: 1.6×. Kittens: 2.5×.

Step 3 — Weight management: overweight cats need calories calculated against their ideal weight using a 0.8× factor. Cat weight loss must be slower than dogs — never more than 0.5–1% body weight per week to avoid hepatic lipidosis (fatty liver disease).

Step 4 — Portion translation: we convert the daily kcal into cans, cups or grams based on the food's calorie content.

Read the full cat feeding guide →

Frequently asked

Cat calorie questions, answered

Why do indoor cats need so few calories?

An average 4.5 kg neutered indoor cat needs only about 180–220 kcal/day — the equivalent of one 5.5oz can of typical wet food. Spaying/neutering drops metabolism by ~25%, and indoor cats burn far fewer calories than wild ancestors. Most "complete and balanced" dry foods pack 380–450 kcal/cup, so the bag's "1/2 to 1 cup" guideline overshoots dramatically.

My cat is obese. Can I just feed her less?

Never crash-diet a cat. Cats deprived of food for as little as 48 hours can develop hepatic lipidosis — a life-threatening fatty liver condition. Weight loss must be slow: 0.5–1% per week, ideally under veterinary supervision and on a prescription weight-management diet.

Is wet food or dry food better for calorie control?

Wet food is generally easier to portion accurately because cans are pre-measured, and it has higher water content (helpful for urinary health). However, both can work — what matters most is total daily kcal, not the form.

Should I free-feed my cat?

Most cats overeat when free-fed dry kibble. Measured meals (2–4 per day, split out using puzzle feeders or timed feeders) prevent obesity and align with cats' natural pattern of multiple small "hunts" per day.

👋 Built by a specialist

Real expertise behind every formula

Dr. Marcus Whitfield

Small-Animal Nutrition Specialist

This calculator uses the standard veterinary RER formula (70 × kg^0.75) with life-stage and body-condition multipliers from NRC 2006 and WSAVA guidelines — the same references your vet relies on.

🎓 Small-Animal Nutrition 📚 AAFCO Reviewed 🌱 3 Years Experience

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How many calories does your cat need?

Daily plan

The formula behind your cat's number

Cat calorie questions, answered

Real expertise behind every formula

Dr. Marcus Whitfield

How many calories does your cat need?

Daily plan

The formula behind your cat's number

Cat calorie questions, answered

Real expertise behind every formula

Dr. Marcus Whitfield

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