🐱 Kitten Growth Predictor
That 900-gram kitten is going to be… how big, exactly? Enter today's age and weight and see the predicted adult size, the growth curve ahead, and whether they're tracking in the typical band for their build.
Your kitten today
Not sure of the age? Eyes open at ~2 weeks, wobbly walking ~3, weaning 4–8, adult teeth arriving around 3.5–6 months — or your vet's estimate beats all of these.
Kitchen scales + a mixing bowl = the classic kitten scale. Weigh at the same time of day for comparable trends.
Large breeds don't just end bigger — they grow for longer (18–24 months), and this model stretches their curve accordingly.
Predicted adult weight
The shaded band is the typical range for this build; the line is your kitten's projected path; the dot is today.
A prediction is a trajectory, not a promise: illness, neutering, diet and plain genetics bend real curves. Weigh weekly and trust the trend — if your kitten stops gaining or loses weight at this age, that's a prompt vet visit, not a wait-and-see.
Why use this predictor?
Early warning is the whole point of weighing
A kitten who stalls or dips in the first months is telling you something weeks before they'd look unwell. Weekly weigh-ins plotted against an expected curve turn "seems small?" into a number you can act on — and show your vet.
"Huge for 6 months" vs actually on-track
A 3 kg six-month-old is alarming if they're heading for 4 kg adult — and perfectly normal if they're heading for 6. The prediction reframes every future weigh-in: not "big or small?", but "on THEIR curve or off it?"
It sizes your life, too
Adult weight decides the carrier, the cat tree sturdiness, the litter box, and the food budget. Knowing whether you're raising a 3.5 kg cat or a 7 kg cat — while they're still palm-sized — makes every purchase the right one first time.
First-year milestones (the awareness version)
| When | What's happening |
|---|---|
| Weeks 2–9 | The socialization window — gentle handling and new (safe) experiences now shape the adult personality. Track it with our Socialization Tracker. |
| Weeks 4–8 | Weaning — from milk to kitten food, gradually, usually led by the mother if she's present. |
| Around weeks 6–9 | The usual window for a first vet visit and the start of the vaccine series — your vet sets the actual schedule for your kitten and area. |
| Months 3.5–6 | Adult teeth arrive (expect extra chewing — and to find the odd baby tooth like a tiny trophy). |
| Around months 5–6 | The spay/neuter conversation with your vet — timing is individual, but the chat belongs around now, before the first heat or spraying makes it urgent. |
| Months 10–12 | Growth slows right down for most cats; transition to adult food happens around the first birthday. Large breeds keep filling out into year two. |
Milestones are orientation, not appointments — your vet personalises the medical ones. This page deliberately sticks to growth and awareness.
Questions people ask
How accurate is the prediction?
Reasonably good after about 8 weeks — typically within ~10–15% for an average kitten on a steady curve. Before 6 weeks, tiny measurement errors swing it wildly; runts and orphans bend it further. Treat the number as "the size of cat to plan for", and re-run it monthly as the curve firms up.
My kitten weighs more than the band. Should I feed less?
Not on a chart's say-so. Kittens are building brain, bone and immune system at full tilt — restricting a growing kitten without a vet's direction is genuinely risky. If your kitten tracks persistently above the band, raise it at a vet visit; if they're simply big-framed, the curve settles the question by 6 months.
The runt of the litter — will they stay tiny?
Often they stay somewhat smaller, but many runts do substantial catching up once they're not competing at the milk bar — especially with their own bowl and no bigger siblings stealing. Their own trajectory matters more than the litter average: steady weekly gains are the reassuring sign.
When do cats actually stop growing?
Most reach ~95% of adult weight by 12 months and full size soon after. Large breeds are the exception — Maine Coons famously keep growing until 18–24 months, sometimes longer, which is why this tool stretches their curve instead of just scaling it up.
Keep exploring
Kitten Socialization Tracker — the other half of the first year · Calorie & Feeding Calculator — kitten portions by the formula · Cat Age Calculator — the stages after kittenhood · All KittyButts tools
Growth projections are estimates based on typical feline growth patterns — a guide for expectations and early awareness, not a health assessment. A kitten who isn't gaining, or who loses weight, needs a vet promptly regardless of what any curve says.