Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

13-18-Month-Old Kitten: What to Expect (Vet-Approved Guide)

Share

cute kitten

When your kitten has turned from a cute ball of fluff to a full-sized killing machine, you may wonder just how much is going to change. After all, the first year of life brings about so many changes.

After your cat’s first birthday, they start to take their first steps into adulthood. They will transform into their big-guy-or-gal selves, reaching full size and further developing their personalities. So, if you have a 13–18-month-old cat, congratulations, you have reached the adult stage. Here’s what you can anticipate.

divider single cat paw oct 2024

13 to 18-Month-Old Kittens: What to Expect After the First Year

Although they are generally still considered adolescents at this stage, your cat is entering the adult chapter of their life. Things become less chaotic and more relaxed as your cat settles into their adult versions.

Diet

When your cat reaches the 13-month threshold, it’s time to think about what diet you’ll offer through adulthood. Most cats are considered full-grown when they reach 12 months of age. So, if you’re feeding commercial cat foods, it’s likely time to switch formulas.

Up until this point, your kitten has probably been eating a higher protein and calorie kitten formula to keep up with their growing body. Since they will no longer need this uptake in nutritional content, you can switch to food that offers health maintenance.

You should consider several factors when selecting a recipe. First, it’s good to brush up on the pet food industry and speak to your vet for advice to see what’s recommended and affordable on your budget. There are many different cat food options but here are some popular ones:

dry kibbles in a container
Image Credit: sophiecat, Shutterstock

Dry Kibble

Dry kibble is still the most popular choice for pet cats. It has a long shelf life and is crafted to provide the appropriate amount of nutrients to your cat. However, it provides no additional moisture to your cat’s diet.

Wet Canned Food

Wet canned food is sure to spark the appetite in your kitties. It offers a bounty of hydration, fresh flavors, and hearty nutrients.

Fresh Food

There are also companies that offer balanced fresh food diets. These are usually highly palatable and digestible and naturally have a high water content.

divider 2 cats

Size & Appearance

At this stage, most cat breeds will be the size they should roughly stay throughout their adulthood, permitting they don’t overeat. Ultimately, the size at this stage will depend mostly on genetics. For example, a Maine Coon cat would be quite large compared to a Singapura and will not be fully grown at 13 months of age.

However, most standard domestic cats grow at similar rates and are sized pretty on point with one another. There should now be visible cues differentiating most males from females. Males are typically noticeably larger than their female counterparts. If they have not yet been neutered, they may even have a lanky body with a blocky head—a classic tomcat look. Fixed males might be a little rounder and not as gaunt. Females are usually dainty with smaller paws and frame. Next to a male, the size differences alone may be visible.

Both sexes of most cats will be completely fully grown by this point. So, there shouldn’t be any increases in height or length, but you might notice them filling out. We want to point out that this is different from gaining weight.

Some cats are very lanky until they hit roughly this age and then they start to thicken up some. But, if your cat looks a little rounder than they used to, it might be time to start measuring out portions and counting calories to trim that middle!

Primordial Pouches

white ragdoll Primordial Pouch
Image Credit: Chase Dekker, Shutterstock

The primordial pouch, (also known as the abdominal or belly flap), is the loose flap of skin along their belly. It usually develops around 6 months, even if it’s not totally visible when they are young and slim. These pouches typically become more pronounced with age and being fixed.

Between 13 to 18 months, you might notice your cat’s little adorable belly droop. Although all cats have a primordial pouch, not all show it. Some are much more pronounced, even with healthy weight, but many become more obvious as a cat gains excess weight.

So, if you notice weight gain throughout the second year, it’s crucial to tell your vet and have them suggest possible diet changes or portion control.

Exercise

Exercise should still be a staple in your cat’s daily routine. Solo indoor cats in particular need regular play time to keep them active and help them maintain a healthy weight.

It’s crucial to keep lots of ways to entertain your cat at home. Many cats enjoy a combination of different activities to keep them busy. Some examples include cat trees, cat scratching posts, exercise wheels, interactive toys, lasers, cardboard boxes and anything with catnip!

During your cat’s first year, you might have already tested out a few types of cat toys. If so, you might already know your cat’s favorites and have several different selections at home. But if you haven’t been shopping for new toys in a while, it’s a good opportunity to do so. Playing with your cat also strengthens your bond, keeps them mentally stimulated and helps them to form good behavioral habits.

kitten playing with bubbles outdoor
Image Credit: Duet PandG, Shutterstock

Sleep

When cats enter adulthood, they can sleep anywhere between 12 to 16 hours per day. But some cats at the 13–18-month-old stage may continue to sleep as much as 15 to 20 hours per day. Ultimately, it depends on their energy levels and bodily requirements. More lackadaisical cats will be partial towards cat naps, grooming sessions, and relaxing with their humans on the couch. More active cats might want to play with you but don’t care too much to cuddle.

Also, as your cat starts to age later in life, you may notice that they start napping more frequently than they do now.

Behavior

Your cat is probably a fully formed independent creature until the food bowl is empty. All cats have different personalities, so it’s hard to speculate how each will behave, but we can certainly give you some pointers. More active cats will likely continue to be active well throughout their first and second years.

Energy levels will change. Some kittens that weren’t extremely active when they were very small may continue to develop into a relaxed, lazy, house cat, or they could become a little more energetic. However, some cats, especially those that were wild and crazy as kittens, might actually end up slowing down a little at this stage.

They will likely have bonded with you very much at this point—but they may have gotten quite set in their ways in others. For example, they may realize they despise the family dog or hate it when they get petted in certain areas.

persian kitten playing on carpet
Image Credit: Zarubina_Yuliya, Shutterstock

divider 2 cats

Ways to Keep Your 13–18-Month-Old Kitty Taken Care of

If you are thinking of new ways to keep your kitty pampered and loved, we thought of a few things that might strike your fancy.

1. Keep Lots of Napping Spots

Now that your cat is calming down a little bit, they likely want more basking, grooming, and napping spots around the home. Every cat loves a good warm, sunny windowsill. But there are tons of other places they love hanging out, too! Cats love vertical spaces as well as little cubbies and hideaways, so it’s always exciting to get them to cat trees, hammocks, and other bedding options.


2. Keep Up with Routine Vet Appointments

Making sure your cat stays healthy their whole life should be a no-brainer on your list of to-dos.

If you have a question about your cat's health or behavior, why not Ask a Vet for Free with Catster. Our veterinary team answers reader questions and provides trusted advice to help you better understand your cat.

askavet on catster

3. Consider Pet Insurance

Your cat is still relatively young and likely has minimal to no health issues. If you haven’t done so already, now is a great time to research a few pet insurance companies to see if a plan meets your needs. Insurance can be fantastic for so many reasons.

Mostly, it brings the owner peace of mind knowing that despite finances, they can give their pet the vet care they require. Some vet care can be extremely expensive, especially in the event of an unknown illness or medical emergency.


4. Don’t Forget to Help with Grooming

Short haired cats will need brushing once a week while long haired ones may even need a daily groom. Ideally your cat will be used to this already and may enjoy the attention, but continue to form positive associations with grooming and nail clipping, you can use treats if needed.


5. Keep Bonding with Your Cat

Don’t ever give up the bond you and your cat share. Continue to grow with your animals by continuing all sorts of interactive activities and laid-back affection sessions. Your cat will absolutely love interacting with you.

Some cats will have different ways of doing this. Some simply like being close to you, others love engaging in play, and many cats just love to be petted by their favorite person.

You can also enrich the lives of your indoor cats by learning to take them on walks on a leash and harness. This can be a little difficult but really fun to accomplish so your cat can explore the great big world outside.

woman smiling in front of adopted kitten
Image by: Iryna Imago, Shutterstock

divider 2 cats

Conclusion

What do you think? Did we explain what you might be experiencing, or help you learn what to expect? If you’re not quite there—hang in there. You’ll get to more solid ground once some of their energy wears down. Some cats can be more rambunctious, while others are chill—so it will ultimately depend on the cat.

Hopefully, we eliminated any surprises for you so you can better plan for the future.


Featured Image Credit: Zenza Flarini, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Catster's Digital Magazine is Back!

Vet-approved health & behavior advice

Real cat stories & community features

The Original Space Invaders – Why Zero Respect for Personal Boundaries Is a Good Thing

Cats have a reputation for being independent, and in many ways they are. But anyone who has tried to work at a laptop...

How Cats Are Helping to Cure Cancer

When most people think about medical breakthroughs, they picture scientists in laboratories and clinical trials involving human patients. Few would imagine that the...

Ask Dr. Paola – My Cat Loves Eating Grass, But It Makes Her Vomit! (June 29, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

Learning to Speak Cat with Anthony Smith

Many cat lovers know me through Learn to Speak Cat and Cattitude – Doggonit, cartoons that explore the often mysterious, occasionally mischievous, and...

More related

Thai vs Siamese Cat: The Differences (With Pictures)

If you’re looking for a cat that wants to stay by your side all day, the Thai cat and the Siamese cat are...

120+ Chinese Cat Names: Ideas for Interesting & Intriguing Cats

Perhaps you’re drawn to Chinese names because you’re fascinated by Chinese culture and history or have roots in the country. Whatever your reason...

6 Most Common Worms & Parasites in a Cat (Vet Answer)

No one likes to think of worms and parasites infesting their pet cat. But what exactly are they, and what are the most...

Serval vs. Savannah Cat: Vet-Reviewed Key Differences (With Pictures)

Servals are African wildcats that have begun growing in popularity as pets with people who crave a more exotic pet, although they are...

Keep reading

Can You Wash a Cat With Just Water? 6 Vet-Reviewed Tips & FAQs

While it’s true that cats spend an excessive amount of time grooming, occasionally, your cat might get into something that their tongue won’t be able to handle. For example, a senior cat may not be able to clean themselves as...

sphynx cat taking a bath in the kitchen sink

Why Do Cats Like Dryer Sheets? Vet-Reviewed Causes & Safety Precautions

Do you like to use dryer sheets when you do your laundry? They make your clothes smell nice, feel soft, and remove static from clothing. Who doesn’t want fresh laundry? As it turns out, cats like dryer sheets, too. Dryer...

Dryer Sheet

How Far Can Cats Hear? Vet-Reviewed Facts & FAQ

Domestic cats are amazing creatures. They can jump five times their height, tap into the earth’s electromagnetic field to navigate, see minute movements in the dark, and feel astonishingly minor changes in airflow with their whiskers. And those aren’t the...

Calico cat with ears pointing up

Can Cats Eat Jicama? Vet-Verified Nutritional Facts & Advice

Pet cats typically consume a commercial diet that meets all their nutritional requirements. However, cats are natural predators, so they go after small mammals, birds, and even reptiles and insects for sport and food. Cats sometimes also gravitate to plants,...

Can Cats Eat Jicama

Do I Need to Put My Cat on a Liquid Diet? Vet-Approved Info & Guide

In most cases, cats will thrive on eating regular cat food throughout their entire lives. There are four main diets for cats that people are familiar with: dry, wet, semi-moist, and raw. Dry and raw diets are at opposite ends...

feeding cat using syringe

How to Train a Cat to Stay Off Counters: 5 Vet-Approved Tips & Tricks

Cats are naturally attracted to high places, but that’s not a good thing when it’s your kitchen counter. Aside from being a nuisance, cats on countertops can be dangerous for them and not hygienic for you. They can walk on...

cat walks on the kitchen table

Acana Cat Food Review 2026: Recalls, Pros & Cons

Review Summary Introduction ACANA has various premium cat food recipes and flavors that are rich with animal protein and nutrients to ensure that your cat gets everything that they need for a complete and balanced meal. It has diets specifically...

Acana Cat Food Review

Why Is My Cat Running Sideways? 7 Vet-Reviewed Reasons

Cats are fascinating pets and behind their every action, there is a myriad of reasons and impulses driving them. Cat’s sideways movement, often called “crab walking”, is no different and encompasses a variety of behaviors with similar movement patterns. Most...

cat running on green grass

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.