How old is a cat in human years? A 1-year-old cat is about 15 in human years, a 2-year-old is about 24, and after that a cat adds about 4 human years per year, whatever its size — so a 10-year-old cat of any size is about 56 in human years. This guide is the cat age chart: the full table, the model behind it, and what the numbers mean for food, exercise, and vet visits. Every figure is an estimate, not an exact conversion. The cat age calculator works out the figure for your cat's exact age and size.
The short version is: a 1-year-old cat is about 15 in human years, a 2-year-old is about 24, and after that a cat adds about 4 human years per year. Use the table below for your cat's age and size, or the cat age calculator for the exact figure. The how old is my cat in human years guide gives the same model with worked examples.
Cat age chart
The table below gives the human-age equivalents for cats aged 1 to 20. Cats age at about the same pace whatever their size, so the chart has one column, not five.
| Cat age | Human years (about) |
|---|---|
| 1 year | 15 |
| 2 years | 24 |
| 3 years | 28 |
| 5 years | 36 |
| 7 years | 44 |
| 10 years | 56 |
| 12 years | 64 |
| 15 years | 76 |
| 18 years | 88 |
| 20 years | 96 |
Read the table from top to bottom and the pattern is clear: a cat ages fast in its first two years — 15 human years in the first year, and 24 by the end of the second — and then adds about 4 human years per year. A 5-year-old cat is about 36, a 10-year-old is about 56, a 15-year-old is about 76, and a 20-year-old is about 96. What changes with size in cats is lifespan, not the pace of ageing: large cats typically live 10 to 14 years, while small and medium cats typically live 12 to 16 years.
The model behind the chart
The rule most veterinarians use for cats is the feline age rule: the first year of a cat’s life equals about 15 human years, the second year brings the total to about 24 human years, and after that you add about 4 human years per cat year. That rule is a rule of thumb, not a precise conversion — individual cats vary — but it is the one most vets use.
The feline rule does not change by size, which is why the cat chart has one column. A small cat and a large cat age at about the same pace, while a small dog and a large dog age at very different paces. What does change with size in cats is lifespan: large cats typically live 10 to 14 years, while small and medium cats typically live 12 to 16 years. Use the stage, not the number, to make decisions about food, exercise, and vet visits.
Life stages for cats
Cats move through three broad life stages, and the boundaries depend on age:
Puppy or kitten (birth to about 12–18 months). Growth is rapid, especially in the first year. Feed a puppy or kitten food, feed little and often, and keep exercise gentle while joints are still developing.
Adult (about 18 months to senior age). Growth is finished and weight should be stable. This is the longest stage and the easiest to manage: consistent food, daily exercise suited to the breed, and a vet check once a year.
Senior (from about 11 years for a cat). The last quarter or so of a typical lifespan. Energy often drops, joints stiffen, and senses dull. Vet checks should move to twice a year, food may need adjusting, and exercise should stay regular but gentler.
Those boundaries are approximate. A cat that is lean, active, and healthy may act like an adult well past its senior boundary, while one with a health problem may need senior care earlier. The when is a cat considered a senior guide gives the thresholds by size.
How to use the chart
Find your cat's age in the left column, then read across to its human years. If your cat is between two ages in the table, take the nearer one — the models are estimates, and a year either way does not change the stage of life. If you do not know your cat's size, use its weight: a small cat is typically 2 to 4 kg, a medium cat 3 to 6 kg, and a large cat 5 to 11 kg. The average cat weight by breed size guide gives the full size tables.
Use the chart to plan care, not to worry: a cat that is a puppy or kitten needs puppy or kitten food and gentle exercise, an adult needs measured food and daily exercise, and a senior needs twice-yearly vet checks and gentler exercise. The number in the chart is a guide to the stage, not a prescription — and a cat's weight, health, and activity matter as much as its age. The cat age chart by breed guide gives the figures breed by breed, and the how to calculate cat age guide gives the step-by-step method.
Common mistakes
The most common mistake is the 'multiply by seven' rule: multiplying by seven gives 35 human years for a 5-year-old cat, against about 36 on the feline rule — and it is wrong in the other direction for puppies and kittens, where a 1-year-old cat is already about 15 in human years, not 7. The second mistake is using the dog model for a cat, or the cat rule for a dog: dogs and cats age differently, and the models are not interchangeable.
The third mistake is taking the number too literally: the models give an estimate of the stage of life, not an exact conversion, and two cats of the same age can be in very different shape. The fourth is forgetting size for dogs: a large dog ages faster than a small one, so a 10-year-old Great Dane is much older in human years than a 10-year-old Chihuahua. The dog years to human years converter and the cat years to human years converter give the same figures as a converter.
For related reading, see the cat age calculator, the cat age calculator guide, the how old is my cat in human years guide, the cat age chart by breed guide, the when is a cat considered a senior guide, the average cat weight by breed size guide.
Frequently asked questions
How old is a cat in human years by size?
A 1-year-old cat is about 15 in human years, a 2-year-old is about 24, and after that a cat adds about 4 human years per year, whatever its size. A 10-year-old cat of any size is about 56 in human years. Use the table above for your cat's exact age and size.
Is the 'multiply by 7' rule right?
No. Multiplying by seven gives 35 human years for a 5-year-old cat, against about 36 on the feline rule — and it is wrong in the other direction for puppies and kittens, where a 1-year-old cat is already about 15 in human years, not 7.
How old is a 10-year-old cat in human years?
A 10-year-old cat of any size is about 56 in human years.
When is a cat considered a senior?
A cat is usually considered a senior from about 11 years, and geriatric from 15. Those are rough guides, and your vet may move the boundary earlier or later depending on your individual cat's health.
How long do cats live?
Typical lifespans are about 12 to 16 years for small and medium cats, and 10 to 14 years for large cats. Those are ranges, not promises.
How do I work out my cat's size?
Use its weight: a small cat is typically 2 to 4 kg, a medium cat 3 to 6 kg, and a large cat 5 to 11 kg. The average weight by breed size guide gives the full size tables.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.