How Big Will My Cat Get Calculator

Your Kitten's Age:

Current Weight:

How This Calculator Works

This calculator uses a formula to estimate your kitten's adult weight based on its current weight and age:

      Final size = (Weight / Age in weeks) × 32
    

At around 16 weeks old, most kittens have reached approximately half of their adult weight. Growth rates can vary by breed, with larger breeds like Maine Coons continuing to grow for up to 2 years.

Did You Know?

The biggest domestic cat ever weighed over 21.3 kg (46 lb)
Northern cat breeds (like Siberian cats, Ragamuffins, and Ragdolls) tend to be larger due to evolutionary adaptations to cold climates
Male cats are typically 20-30% larger than females of the same breed

You’ve just found your new favorite how big will my cat get calculator. Our tool not only estimates the future weight of your favorite feline – it’ll also show you how to tell how big a kitten will get and guide you through all the necessary calculations, step by step! 🐱

Read on to discover:

When do cats stop growing;
How big do cats get; and
When does puberty start for your cat.

How to calculate how big will my kitten get?

It’s actually pretty easy! All you need to predict how big will your kitten get is:

Your cat’s current age; and
Your cat’s current weight.

If you’ve already gathered all the information, let’s use the equation taken from our how big will my cat get calculator:

Final size = (Weight / Age) * 32

Where:

Age is given in weeks.

💡 At 16 weeks old, your cat will reach half of its final weight.

In what follows, we will discuss how big cats get.

Fancy some other catculations? 🙀Take a look at our other feline tools:

Cat pregnancy calculator;
Cat age calculator;
Cat chocolate toxicity calculator;
Cat BMI calculator; and
Catculator.

How big can a cat get?

The biggest domestic cat ever weighed over 21.3 kg (46 lb), while the biggest feline on earth, a liger (lion + tiger mixture) called Hercules, weighed over 412.2 kg (922 lb)!
The biggest domestic cat breeds are Siberian cat, Ragamuffin, and Ragdoll.
The Guinness World Records recognizes the longest domestics cats. The trophy currently belongs to a 123 cm (48.5 in) long Stewie.

As you can see, the answer to the question how big do cats get is not as straightforward as it seems!

💡 Usually, all the northern breeds that originated in colder climates tend to be larger. That’s because it’s easier to keep yourself warm when your body surface-to-body volume ratio is the lowest possible (aka, it’s better to be large and round.

How to use the how big will my cat get calculator?

It’s probably not possible to make it any easier!

Enter your cat’s age.
Enter your cat’s weight.
You may choose between imperial and metric units – we’ve got everything that you need!
Hey, you’re already there! Enjoy your results. 🎉

FAQs

When do kittens stop growing?

Many sources say that kittens become adult cats after approximately 1 year of growing – in reality, this process varies heavily and ranges from 32 to 52 weeks.

How to calculate my cat’s puberty start?

The calculation is short and simple:

Find exactly when your cat was born.
Add the number of months, depending on your cat’s sex:
- If it’s a girl, add 6 months.
- If it’s a boy, add 5 months.
This method allows you to estimate the earliest possible start of your cat’s puberty. Watch out for sexual maturity signs, such as urine marking or increasing affection and vocalization.