What Size Cat Carrier Do I Need? Measure in 3 Easy Steps
Quick answer: to work out what size cat carrier you need, measure your cat standing up from nose to the base of the tail, then from the floor to the top of the head. Add about 5 cm (2 in) to each number. Your cat should be able to stand, turn around and lie down, but the carrier should still feel snug enough that they don't slide around.
From the Cutier Store team: "what size cat carrier do I need?" lands in our inbox almost every week, especially before holiday trips. Size charts on their own don't answer it, because the right fit also depends on where you're going. So this guide walks you through measuring, then matching the size to the trip. When you're ready to compare styles, our cat carriers for every kind of trip are all in one place.
Why carrier size matters more than you think
A carrier is your cat's little room on the move. Get the size wrong and the trip gets harder for both of you.
- Too small: your cat can't stand or shift position, which is uncomfortable and stressful.
- Too big: your cat slides around every time you walk or brake. A big, empty space can also feel less safe to a nervous cat.
- Just right: room to stand, turn and curl up, with sides close enough to lean on.
The UK charity Cats Protection gives the same core rule in its guide to choosing a cat carrier: a little taller and longer than your cat, but snug enough that they don't fall about.
How to measure your cat for a carrier in 3 steps
You only need a soft tape measure, a few treats and about two minutes. Do it when your cat is relaxed, like after a meal.
Step 1: measure length
While your cat is standing, measure from the tip of the nose to the base of the tail. Don't include the tail itself. Cats curl their tail around them when they settle.
Step 2: measure height
Measure from the floor to the top of the head while your cat stands naturally. If your cat has upright ears that brush things, measure to the ear tips instead.
Step 3: add breathing room
Add about 5 cm (2 in) to both numbers. That gives you the minimum inside length and height to look for. Then weigh your cat: step on a scale holding them, then subtract your own weight. Many soft carriers are sized by weight as well as dimensions.
Tip: check the inside measurements if a listing gives them. Padding, frames and pockets can make the outside look bigger than the space your cat actually gets.
What size cat carrier do I need for each type of trip?
This is the part most size guides skip. The same cat might need a different fit for a vet visit than for a flight.
| Trip | What to aim for | Good style |
|---|---|---|
| Vet visit | Your measurements plus 5 cm, with a top opening for easy exams | Sturdy carrier that opens at the top and front |
| Car journey | Room to lie down fully, and a shape that can be belted in | Rolling carrier or flat-based carrier |
| Flight in the cabin | Your airline's under-seat limit first, then your cat's measurements | Soft-sided carrier that can squash slightly |
| Short walk or day out | A snug fit plus space to expand at rest stops | Expandable backpack or front carrier |
| Two small cats | One carrier per cat, or separate compartments | Multi-pet trolley with layers |
Flying soon? Every airline sets its own carrier limits, and they can change by route and plane. Check the rules on your airline's website before you buy, not after.
Weight matters too: yours and your cat's
A 5 kg cat in a carrier can feel heavy after ten minutes of walking. Think about how far you'll actually carry it.
- Short distances: a handle or shoulder strap is fine.
- Longer walks: padded backpack straps spread the weight across both shoulders.
- Airports and train stations: wheels save your back. Just keep the carrier level so your cat isn't tipped around.
Special cases: kittens, big cats and multi-cat homes
Kittens
A kitten-sized carrier will be outgrown within months. If your budget allows only one, choose a size that fits an average adult cat. Add a folded blanket for now so your kitten doesn't slide around.
Large or fluffy cats
Long fur makes cats look bigger than they are. Measure the body, not the fluff, but don't squeeze. If your cat sits between two sizes, go one size up.
More than one cat
Most vets and shelters suggest a separate carrier for each cat. Even best friends can get stressed and swat each other in a tight space.
Is a backpack carrier the right size for my cat?
Honest answer: backpacks suit confident cats on short outings best. Cats Protection advises against them for long carries, because many are too small for a cat to stand and reposition. For anxious cats or long vet waits, a carrier with more room is kinder.
If you do choose a backpack, look for:
- An expandable section you can open out when you sit down
- A firm base so your cat isn't sagging into a pouch
- Mesh on more than one side for airflow
- An inner safety tether that clips to a harness
Already picked one? Our 10-day plan for backpack training helps your cat see it as a cozy den, not a trap.
How to choose: carriers we love
Here are three of our carriers and who they suit. We only list details from our own product pages.
- Expandable pet carrier backpack: opens out for extra room at rest stops, with mesh panels, padded straps, top, side and front openings, and an inner leash clip. Suitable for cats and small dogs up to 8 kg.
- Bubble backpack in five sizes: sized S to XXL for cats from 0.5 to 6 kg, so it's easy to match to your cat's weight.
- Rolling carrier with silent wheels: switches between trolley and shoulder bag, with mesh sides and a clear window, for airport days and long drives.
Driving instead of flying? Our holiday road trip plan for cats covers where the carrier should sit in the car.
The 5-minute fit test at home
Once your carrier arrives, test it before the big day.
- Leave it open on the floor with a blanket that smells of home.
- Toss a treat inside and let your cat walk in alone.
- Watch: can your cat turn around without folding up awkwardly?
- Can they lie on their side without pressing against both ends?
- Zip it closed for a few seconds, then reward and open it.
If your cat looks cramped, swap sizes now rather than on travel day.
Cat carrier size checklist
- ☐ Measured length, nose to base of tail
- ☐ Measured height, floor to top of head
- ☐ Added about 5 cm (2 in) to each
- ☐ Weighed my cat
- ☐ Checked inside dimensions, not just outside
- ☐ Checked my airline's limits (if flying)
- ☐ Did the 5-minute fit test at home
Found your cat's perfect fit? 🐾
Explore our carriers and travel bags with free shipping on every order. Orders are dispatched within 24–48 hours and usually arrive in 2–12 days, so there's time to practise before your trip.
FAQ
Should a cat carrier be bigger than the cat?
Yes, a little. Aim for about 5 cm (2 in) more than your cat's standing length and height. Much bigger than that, and your cat may slide around and feel less secure.
Can a cat carrier be too big?
It can. A very large carrier is harder to carry level, and your cat can be thrown about when you move. Snug and secure usually beats roomy and wobbly.
What size carrier does a 5 kg cat need?
It depends on your cat's shape, so measure rather than guess. As a starting point, many soft carriers list a weight range. Choose one where 5 kg sits comfortably inside the range, not at the very top.
Do airlines allow any size cat carrier in the cabin?
No. Each airline sets its own under-seat size and weight limits. Check your airline's pet policy before buying, and ask your vet whether your cat is fit to fly.
Is it okay for two cats to share one carrier?
It's usually better to use one carrier per cat. Stress can make even close companions swat each other in a small space.
