How we turn cat years into human years
Cats do not age at a steady pace. The first two years are a blur of growing up, and after that everything slows down. So we do not multiply by 7 — we use the three-step rule everyone actually uses.
The three-step rule
First year
A kitten goes from helpless to fully grown in twelve months, so year one counts as 15 human years.
Second year
Year two is the teenage-to-adult stretch, so it adds another 9 human years — 24 in total.
Every year after
Once past 24, each extra cat year adds about 4 human years. Steady, dignified, and a little grumpy.
The whole scale
A quick lookup. Take the cat age on the left, read the human age on the right.
| Cat age | Human years | Life stage |
|---|---|---|
| 1 year | 15 | Junior |
| 2 years | 24 | Junior |
| 3 years | 28 | Adult |
| 5 years | 36 | Adult |
| 8 years | 48 | Mature |
| 10 years | 56 | Senior |
| 15 years | 76 | Geriatric Legend |
| 20 years | 96 | Geriatric Legend |
The six life stages
Every cat gets sorted into a stage, which is also what sets their daily kibble appetite below.
A tiny chaos goblin running purely on vibes and gravity.
40 g / day
Legally a teenager. Emotionally a 3am thunderstorm.
70 g / day
In their prime — peak napping, peak judgment, peak floof.
160 g / day
Knows exactly which chair is theirs, and that it is all of them.
145 g / day
Distinguished. Opinionated. Commands better snacks than you.
130 g / day
Has seen empires rise and fall, and slept through most of it.
120 g / day
Where the other numbers come from
The four figures on every report card are plain multiplication, nothing clever.
- Days on this planet
- Days on this planet is simply the number of days since the birthday.
- Naps (approx.)
- Cats sleep about 16 hours a day, so we multiply days by 16 to get napping hours. Naps are those hours in roughly 3-hour chunks.
- Heartbeats so far
- A resting cat’s heart beats around 130 times a minute, so days × 24 × 60 × 130 gives the total.
- Kibble eaten (approx.)
- Kibble is the stage’s daily appetite in grams, multiplied by the number of days. It is the average for a healthy adult cat, so consider it a rough estimate.
The honest caveat
This is a rule of thumb, not a diagnosis. Real ageing depends on breed, size, whether a cat goes outside, and how well they are looked after. For anything that actually matters, ask a vet.