Cat Weight Chart Calculator — Healthy Range by Breed & Age
Is your kitty’s weight in the healthy range for her breed? This calculator compares current weight to the breed-specific healthy range — Maine Coons, Siamese, and Persians sit at very different baselines, so a 12-lb cat can be underweight as a Maine Coon or obese as a Siamese. The breed ranges follow the AAHA/AAFP Feline Life Stage Guidelines and CFA breed standards.
Calculator
How to use the cat weight chart calculator
- Enter breed or breed mix — Breed dramatically affects expected weight range. Use “mixed/domestic” if unknown.
- Enter age + current weight — Monthly tracking helps catch weight trends early.
- Output shows breed percentile + BCS target — Not just a number — context for whether that weight is healthy for your cat's specific breed and bone structure.
- Verify with body condition score — Three-point check: ribs, waist, belly tuck. BCS 4–5/9 = ideal.
Why breed matters more than you think for cat weight
The standard “8–12 lb adult cat” range is a domestic-shorthair average and badly misrepresents purebred ranges. A 10-lb Maine Coon male is significantly underweight; a 10-lb Siamese female is moderately obese. Breed-specific charts (the calculator above) are the minimum accurate reference for pedigreed cats; BCS remains the final tiebreaker regardless of breed.
| Breed | Male adult (lb) | Female adult (lb) |
|---|---|---|
| Domestic shorthair (mixed) | 8–12 | 7–10 |
| Maine Coon | 15–25 | 10–15 |
| Ragdoll | 15–20 | 10–15 |
| British Shorthair | 11–17 | 9–12 |
| Persian | 9–12 | 7–10 |
| Siamese | 8–10 | 6–8 |
| Abyssinian | 9–11 | 6–9 |
| Bengal | 10–15 | 8–12 |
| Russian Blue | 9–12 | 7–10 |
| Sphynx | 8–11 | 6–9 |
Body condition score — the real measurement
Scale weight alone is misleading without body condition context. A BCS of 4–5 on the 9-point WSAVA scale represents ideal body composition — adequate muscle mass, minimal body fat, and proper skeletal proportion. The three-check BCS assessment works for any cat regardless of breed, age, or coat:
- Rib check: Run flat hands along the cat's sides. Ribs should be easy to feel under a thin layer of fat, like feeling knuckles through the back of your hand. Buried under thick fat = BCS 7+ (overweight). Visibly sticking out = BCS 1–3 (underweight).
- Waist from above: Look down at the cat standing. A clear inward narrowing behind the ribs (hourglass shape) = BCS 4–5. Straight-sided or bulging outward = BCS 7+.
- Abdomen from the side:The belly line should slope upward from the ribcage to the hind legs — an “abdominal tuck.” Hanging belly = BCS 7+ (overweight); hanging belly in neutered cats over 4 years old with a “primordial pouch” (loose skin flap) is normal and not fat.
Photograph your cat monthly from above and from the side against a plain background to track trends that are otherwise easy to miss day-to-day.
Feline weight terminology
- Body Condition Score (BCS 1-9)
- Visual + palpation grade — 4-5 is ideal for cats; over 6 doubles diabetes risk.
- Breed standard weight
- Healthy adult weight range published by CFA / TICA — varies hugely (5-25 lb depending on breed).
- Muscle Condition Score (MCS)
- Separate from BCS — assesses lean muscle, important in senior cats losing mass (sarcopenia).
- Sarcopenia
- Age-related muscle loss in senior cats; protein intake of 6+ g/kg/day mitigates it.
Frequently Asked Questions
How much should my cat weigh at different ages?
Average adult domestic shorthair: 8–12 lb. But breed matters enormously — Siamese: 6–10 lb; Maine Coon: 10–25 lb; Ragdoll: 10–20 lb; Persian: 7–12 lb; British Shorthair: 9–17 lb. Always verify weight with body condition score (BCS 1–9, with 4–5 ideal) — a large-boned cat at the high end of breed range may be fine, while a small-boned cat at the same weight is obese.
How do I body-condition-score my cat?
Three checks: (1) Rib palpation — ribs should be felt with light finger pressure, not visible, not buried under fat. (2) Waist tuck — from above, see a clear narrowing behind the ribs. (3) Abdominal tuck — from the side, see slight upward slope from ribs to hind legs. BCS 4–5/9 passes all three. BCS 7+ (overweight) fails waist tuck; BCS 8–9 (obese) fails all three.
Why is my cat gaining weight?
The most common causes in order: (1) Free-feeding dry food with no portion control. (2) Reduced activity — indoor lifestyle vs. their evolved activity budget. (3) Post-neutering metabolic drop (up to 25 %). (4) Aging (metabolism slows 10–15 % per decade). Less commonly: hypothyroidism (rare in cats), diabetes (weight loss is more typical), fluid retention from heart or kidney disease.
Why is my cat losing weight?
Unintended weight loss in cats requires prompt veterinary assessment — the list of causes is long and many are serious. Common: hyperthyroidism (over age 10), diabetes, chronic kidney disease, inflammatory bowel disease, intestinal lymphoma, dental disease (pain on eating), parasites. Always take a cat losing more than 5 % of body weight over a month for bloodwork and a thyroid check.
How often should I weigh my cat?
Monthly is ideal for healthy adult cats; weekly for kittens (under 6 months), seniors (over 10 years), and any cat with a weight-sensitive condition (diabetes, CKD, recent weight change). Use a digital kitchen scale for cats < 10 lb; a bathroom scale works for larger cats (weigh yourself, then yourself holding the cat, subtract). Record weights over time — a trend matters more than any single reading.
Is obesity really that bad for cats?
Yes. Obesity in cats is associated with 2–4× higher risk of diabetes mellitus, hepatic lipidosis (especially if the cat ever stops eating), osteoarthritis, urinary tract disease, and shorter lifespan. A 2011 study showed obese cats lived on average 2.8 years less than lean-body-condition cats. Weight loss is harder in cats than dogs and must be done slowly — never crash-diet a cat, because rapid calorie restriction triggers hepatic lipidosis.
How much should a kitten weigh?
Newborn: 3–4 oz. 1 week: 6–7 oz. 2 weeks: 8–10 oz. 4 weeks: 14–16 oz (about 1 lb). 8 weeks: 2 lb. 12 weeks: 3 lb. 16 weeks: 4 lb. 6 months: 6–7 lb for most breeds. Kittens should gain 0.25–0.5 lb per week during active growth. Slow weight gain or weight loss in kittens is always a vet emergency — their reserves are minimal.
Sources & References
- [1]WSAVA Global Nutrition Guidelines (BCS System) — World Small Animal Veterinary Association
- [2]AAHA/AAFP Cat Life Stage Guidelines (Weight Assessment) — American Association of Feline Practitioners
- [3]Obesity in Cats — Clinical Overview — Merck Veterinary Manual
- [4]Body Condition Score Chart — Purina — Purina Nutrition Center
Related Calculators
- Cat Age CalculatorConvert your cat's age to human years using the official AAHA/AVMA Feline Life Stage Guidelines. Indoor vs outdoor lifespan compare.
- Cat Pregnancy CalculatorEstimate your queen cat's due date (63–67 day gestation) with a weekly tracker, vet milestones and kittening-box prep timing.
- Cat Calorie CalculatorCalculate daily kcal for your cat using the RER formula with neutered/intact, kitten, senior and BCS adjustments. AAFP life-stage based.
- Cat Litter CalculatorCalculate how much cat litter you need per month for 1–5 cats. Supports clay, clumping, crystal and pine substrates.
- Cat Water Intake CalculatorCalculate your cat's daily water needs based on weight and diet (wet vs dry). Dehydration warning signs and prevention tips.
- Kitten Weight ChartCheck if your kitten's weight is on track. Shows expected weight by age in weeks from birth to 12 months with flags for underweight/overweight.