Cat Weight Calculator — Is My Cat Overweight?
This cat weight calculator tells you whether your cat sits in a healthy weight range. It applies the WSAVA Body Condition Score (the 1-9 scale used in clinics worldwide), the AAHA Resting Energy Requirement formula, and breed-specific weight tables. Enter your cat's details below to see an instant report covering Body Condition Score, ideal weight in kilograms and pounds, daily calorie target, and a safe weight-loss timeline.
Cat Weight Calculator
Enter your cat's details below. Results follow WSAVA veterinary guidelines.
Weigh yourself alone, then again holding your cat. Subtract the difference.
View your cat from above and from the side. Pick the silhouette that matches.
View the formula used
Daily calories (DER) = RER × life-stage factor
Safe weight loss = 0.5%–2% body weight per week
Source: WSAVA Global Nutrition Guidelines & AAHA Weight Management Guidelines.
How to Use the Cat Weight Calculator
Each step takes under 30 seconds. The full calculation finishes in roughly two minutes.
- 1
Weigh your cat accurately
Step on a bathroom scale alone and write down the number. Pick up your cat. Step on again. The difference is your cat's weight. Digital pet scales give cleaner results, especially for kittens under 5 lbs.
- 2
Enter breed, age, sex, and neuter status
Breed sets the ideal weight range. Sex narrows it (males typically run 2-5 lbs heavier than females in the same breed). Age determines life stage. Neuter status adjusts the calorie multiplier by 20-30%.
- 3
Pick the matching body type silhouette
Look at your cat from above. A healthy cat shows a visible waist behind the ribs. From the side, the abdomen tucks up. Run your palm along the rib cage. Ribs should feel like the back of your hand — not buried in fat, not sharp like knuckles.
- 4
Read the full report
The calculator returns four results: Body Condition Score (1-9), ideal weight range, daily calorie target in kcal, and weeks to reach a healthy weight if loss is needed.
- 5
Share results with your veterinarian
The output works as a starting point for a vet visit. Veterinarians can adjust the calorie target for hyperthyroidism, diabetes, chronic kidney disease, and other conditions that change energy needs.
What Is a Cat Body Condition Score?
The Body Condition Score (BCS) is a hands-on assessment that grades body fat in cats. The World Small Animal Veterinary Association (WSAVA) standardised the 1-9 scale in 2011. Score 1 means emaciated. Score 5 is ideal. Score 9 means severe obesity. Each step up the scale represents roughly 10-15% extra body fat.
The BCS works across every breed. A 6 lb Singapura and a 22 lb Maine Coon can both score a healthy 5. Veterinarians assess three things: rib coverage by feel, waist visibility from above, and the abdominal tuck from the side. The Purina BCS chart and the WSAVA chart both use the same 1-9 scale, though some clinics also use a simpler 1-5 scale.
A 2021 study published in the Journal of Feline Medicine and Surgery found that BCS agreement between veterinarians and owners is poor — owners consistently underestimate their cat's BCS by 1-2 points. This means most overweight cats are unrecognised by their owners.
Read more about how frame and breed affect healthy weight in our guide to cat size and weight ranges, or view the official BCS chart from the WSAVA Global Nutrition Guidelines.
Average Healthy Cat Weight by Breed
Breed shapes adult weight more than any other single factor. The table below lists typical adult ranges for 20 popular breeds. Frame and body type matter as much as the scale reading.
| Breed | Female (lbs) | Male (lbs) | Frame |
|---|---|---|---|
| Maine Coon | 10–15 | 15–25 | Large |
| Ragdoll | 8–15 | 12–20 | Large |
| Norwegian Forest | 8–12 | 12–16 | Large |
| Savannah | 12–20 | 15–25 | Large |
| Siberian | 8–12 | 12–17 | Large |
| British Shorthair | 7–12 | 9–17 | Medium-Large |
| Persian | 7–10 | 9–14 | Medium |
| Bengal | 7–10 | 10–15 | Medium |
| American Shorthair | 6–12 | 11–15 | Medium |
| Domestic Shorthair | 6–10 | 8–12 | Medium |
| Russian Blue | 7–10 | 10–12 | Medium |
| Scottish Fold | 6–9 | 9–13 | Medium |
| Sphynx | 6–8 | 8–12 | Medium |
| Abyssinian | 6–8 | 8–10 | Small-Medium |
| Siamese | 5–8 | 8–12 | Small-Medium |
| Burmese | 6–8 | 8–12 | Small-Medium |
| Oriental Shorthair | 5–8 | 8–10 | Small-Medium |
| Devon Rex | 5–8 | 7–9 | Small |
| Cornish Rex | 5–7 | 6–9 | Small |
| Singapura | 4–6 | 6–8 | Small |
Unsure of your cat's breed? Try our cat breed identifier by photo or take the cat breed quiz. You can also browse the most common domestic cat breeds.
Why Cat Obesity Matters: The Data
The Association for Pet Obesity Prevention (APOP) reports that 61% of cats in the United States are overweight or obese as of its 2022 survey. The UK PDSA Animal Wellbeing Report puts the UK figure at around 53%. Both figures have risen steadily since 2010.
Two extra pounds on a 10 lb cat equals roughly 30 extra pounds on an average human. The fat does the same damage. Overweight cats face sharply higher risk of these conditions:
- Type 2 diabetes mellitus — risk increases 4-fold in obese cats; weight loss can put diabetes into clinical remission in roughly 50% of cases.
- Hepatic lipidosis — fatty liver disease, the most common feline liver disorder; mortality reaches 50-90% without aggressive treatment.
- Osteoarthritis — affects 60-90% of obese cats over age 12; reduces jumping height and mobility.
- Feline lower urinary tract disease (FLUTD) — obesity is one of the top three risk factors.
- Hypertension and certain cancers, including mammary carcinoma.
A 2003 study by Scarlett and Donoghue, published in the Journal of the American Veterinary Medical Association, found that obese cats had a 2.8x higher risk of premature death than lean cats. The 2011 Purina Lifespan Study showed that lean-fed dogs lived 1.8 years longer; comparable cat studies suggest a 2-3 year lifespan reduction in obese cats.
The good news: a 9% body weight loss can resolve diabetes in some cats and significantly improves mobility scores within 8 weeks.
How Many Calories Does a Cat Need Per Day?
Veterinary nutritionists calculate cat calorie needs in two steps. Step one finds the Resting Energy Requirement (RER) — the calories needed for basic functions at rest. Step two multiplies the RER by a life-stage factor to get the Daily Energy Requirement (DER).
DER = RER × life-stage factor
The 0.75 exponent comes from metabolic scaling research by Max Kleiber in the 1930s and remains the standard for mammalian energy modelling. The life-stage factors below come from the AAHA Nutritional Assessment Guidelines:
| Life stage | Multiplier |
|---|---|
| Kitten, 0-4 months | RER × 2.5 |
| Kitten, 4-12 months | RER × 2.0 |
| Intact adult | RER × 1.4 |
| Neutered adult | RER × 1.2 |
| Weight loss | RER × 0.8 |
| Senior (11+ years) | RER × 1.1 – 1.6 |
| Pregnant queen | RER × 1.6 – 2.0 |
| Lactating queen | RER × 2.0 – 6.0 |
A 4.5 kg neutered adult cat needs roughly 70 × 4.5^0.75 × 1.2 ≈ 260 kcal per day. The same cat eating one cup of typical dry kibble (which averages 350-400 kcal) exceeds its needs by 35-50% every day. That gap explains why so many indoor cats become overweight.
When to See a Veterinarian
⚠️ Book a vet visit promptly if any of these apply:
- Your cat scores BCS 1-3 (underweight) or BCS 7-9 (overweight or obese)
- Sudden weight loss of more than 10% in under 4 weeks
- Rapid weight gain without a change in diet
- Loss of appetite for more than 24-48 hours — hepatic lipidosis develops fast in cats
- Visible ribs, spine, or hip bones with muscle wasting (a sign of sarcopenia or disease)
- Trouble grooming the lower back or rear end — a hallmark sign of obesity
- Increased thirst, lethargy, or changes in litter-box habits
Never crash-diet a cat. Losing more than 2% body weight per week triggers hepatic lipidosis, a life-threatening condition. Always work with a veterinarian on a controlled weight plan.