The honest answer is two numbers. Life expectancy at birth is 11.7 years across all cats in the RVC's 2024 VetCompass study of UK veterinary records, crossbreds at 11.9. But established indoor pet cats, the ones that made it through kittenhood into a home, are commonly cited at 13–17 years, and plenty reach 20. Breed spreads the range further than anything else you can read off a cat: Burmese and Birman sit at 14.4 years, Sphynx at 6.7. Here's the full breed table, the indoor-outdoor gap, and the two levers the data actually quantifies.
Life expectancy at birth averages in every death, including kittens lost in their first weeks and young cats hit by cars. Follow only cats that reached adulthood and moved indoors, and the survivors pull the average up to the 13–17 range US vets cite. Neither number is wrong, they answer different questions, and knowing which one a website is using tells you whether its breed table is trustworthy.
The RVC study (Teng et al., 2024, in the Journal of Feline Medicine and Surgery) is the largest modern life table for pet cats: roughly 7,900 deaths across UK veterinary clinics, 2019–2021. Its breed numbers are what the calculator below uses.
| Breed | Life expectancy at birth | Versus crossbred |
|---|---|---|
| Burmese | 14.4 yrs | +2.5 |
| Birman | 14.4 yrs | +2.5 |
| Crossbred (domestic shorthair/longhair) | 11.9 yrs | baseline |
| Siamese | 11.7 yrs | −0.2 |
| British Shorthair | 11.7 yrs | −0.2 |
| Persian | 10.9 yrs | −1.0 |
| Ragdoll | 10.3 yrs | −1.6 |
| Maine Coon | 9.7 yrs | −2.2 |
| Bengal | 8.5 yrs | −3.4 |
| Sphynx | 6.7 yrs | −5.2 |
Two patterns worth knowing. Crossbreds outlive purebreds by about 1.27 years on average, the shelter moggie is a statistical longevity bet. And the bottom of the table is where concentrated genetic disease lives: the Sphynx's 6.7 years tracks its epidemic of hypertrophic cardiomyopathy, and Bengals carry inflammatory-bowel-lineage disease. If you're choosing a purebred, the breeder's health testing matters more than the breed's average.
Breed, sex, age and weight in, adjusted life expectancy and years remaining out.
Cat Life Expectancy Calculator →| Lifestyle | Commonly cited lifespan |
|---|---|
| Indoor only | 13 – 17 yrs |
| Indoor-outdoor mix | Not significantly different from indoor (UC Davis) |
| Outdoor only, free-roaming | 2 – 5 yrs |
A caveat the internet skips: the 2–5 year outdoor figure is repeated everywhere but its original study is hard to trace, and it describes truly free-roaming cats, not the house cat with garden privileges. UC Davis's feline longevity work found mixed indoor-outdoor cats did not die significantly sooner than indoor-only ones. So the practical split isn't "inside good, outside death," it's "unsupervised roaming is the risk, and supervised or enclosed outdoor time buys the enrichment cheaply."
One more wrinkle: the RVC's UK data found indoor-only cats lived slightly shorter lives, likely because UK cats kept indoors are often kept in for health reasons to begin with. Confounding, not causation, and it doesn't transfer to the US pattern where outdoor access means traffic. Read it as a reminder that lifestyle statistics are messier than breed statistics.
Everything else, annual exams from middle age, dental care, keeping water attractive to a cat with early kidney changes, has biology behind it but no published coefficient. Do them anyway.
Life expectancy is a planning tool, not a countdown. The useful moments: deciding when to start senior bloodwork (around 10), whether pet insurance still pencils at a given age (premiums climb steeply past 8), and how hard to push a weight-loss plan that the cat is resisting. Cats also break life tables on the long side, a cat that reaches 15 has exited the statistics' jurisdiction entirely, and vets routinely see 15-year-olds live to 18 or 20.
To translate your cat's age into human terms, the cat age calculator uses the 15/9/4 rule (a 1-year-old cat is a 15-year-old human, 2 maps to 24, then 4 per year). Dogs get the same treatment by size in the dog life expectancy calculator, and the pet insurance calculator prices the monthly-premium side of planning for the worst.
US veterinary sources commonly cite 13-17 years for indoor pet cats, with many reaching 20. Those figures describe established house cats that survived kittenhood. Life expectancy at birth, which averages in every early death, is lower: 11.7 years across all cats in the RVC's 2024 UK VetCompass data, with crossbreds at 11.9.
Free-roaming outdoor-only cats are commonly cited at 2-5 years, the traffic, predator, and exposure toll. UC Davis researchers found cats with mixed indoor-outdoor access did not differ significantly from indoor-only cats, so the penalty concentrates on cats that live outdoors full time. The 2-5 year figure is the standard veterinary citation even though its original study is hard to trace.
Mixed breeds, by about 1.27 years on average in the RVC 2024 data, crossbreds at 11.9 years versus purebreds around 10.6. Within purebreds the spread is enormous: Burmese and Birman at 14.4 years at the top, Sphynx at 6.7 at the bottom. A well-bred cat of a long-lived breed beats the average; a breed with concentrated genetic disease drags it.
The RVC study quantified it: lifespan drops about 0.02 years for every 100 g of body weight. That sounds tiny, but a cat carrying 4 extra pounds (about 1,800 g) gives up roughly 0.36 years, plus the diabetes and joint disease that come with obesity. Weight is the one lifespan lever with a published coefficient, and indoor cats on free-fed dry food creep up on it silently.