If you have ever stood in your living room holding a tape measure while a cat gives you a look that says absolutely not, you already know why so many people search for how to measure a cat for a costume before they buy one. The good news is that it takes less time than most cats will tolerate being held still, and there is really only one number that matters.
Clementine, our resident garden cat, is not a fan of being handled for longer than strictly necessary. Her measuring session, in true Clementine fashion, lasted about eleven seconds before she wandered off to supervise the yard instead. That was plenty of time, because measuring a cat for a costume only takes one pass with a soft tape measure.
The One Measurement That Actually Decides Size
Every costume size chart, whether it is the Bat Wings Pet Costume or the Pet Costume Hoodie, is built around chest girth — the measurement around the widest part of your cat's ribcage, just behind the front legs. Weight is not part of the equation anywhere in our sizing, and for good reason: two cats can weigh exactly the same and have completely different builds. A long, lean nine-pound cat and a compact, barrel-chested nine-pound cat need different sizes, even though a scale would tell you they are identical.
How to Take the Measurement
Stand your cat up on a flat surface — not sitting, not curled into a loaf, not draped over your arm. A seated or curled cat compresses its ribcage and will measure smaller than it really is, which is the single most common reason a costume ends up too tight. With your cat standing normally, wrap a soft fabric tape measure around the chest just behind the front legs, snug enough to stay in place but loose enough to slide a finger underneath. Write that number down before your cat loses patience and walks away — Clementine's window of cooperation was generous by cat standards, and yours might be shorter.
If your cat squirms before you get a clean read, try again after a meal or during a calm moment rather than mid-play. A treat held at nose height buys a surprising number of extra seconds.
Matching the Number to a Size Chart
Once you have a chest measurement in hand, match it directly to the product's chart rather than estimating. The Bat Wings costume runs in centimeters: size S covers a 36–42 cm chest, size M covers 40–60 cm, and size L covers 55–85 cm. The Pet Costume Hoodie uses inches instead: XS is 12.5", S is 15", M is 17.5", L is 19.5", XL is 22", and 2XL is 24.5" — so double-check which unit you are reading before you order.
If your cat's measurement lands exactly between two sizes on either chart, size up rather than down. That is the only situation where going a size larger makes sense — never buy a size up "for room to grow," since cats do not grow into costumes the way kittens grow into collars, and a costume that is too loose will twist, slide, and get pulled off within minutes.
Why a Correct Measurement Changes How Long They'll Wear It
A costume sized from a real chest measurement sits still on a cat's body, which is the entire difference between a cat who tolerates a costume for an evening and one who claws it off in ninety seconds. Both the Bat Wings design and the Pet Costume Hoodie are built with free paws and nothing covering the face, but fit still does most of the work — a well-measured cat barely notices the costume is there, while a poorly measured one spends the whole time trying to adjust it.
This matters just as much for dogs, if you happen to be sizing for both species in the house. Our full dog costume sizing guide walks through the same standing-measurement method with photos, and the underlying rule — chest measurement over weight, every time — is identical for cats.
No Soft Tape Measure on Hand? Here's a Backup
If you cannot find a fabric tape measure, a piece of string or ribbon works almost as well. Wrap it around your cat's chest the same way, behind the front legs, pinch the spot where the ends meet, then lay the string flat against a ruler or yardstick to read the length. It takes one extra step compared to a tape measure, but the result is just as accurate, and it means a missing tape measure is never a reason to guess at a size instead of measuring properly.
What you want to avoid is estimating from a photo, from memory, or from how a costume fit a previous cat. Even cats of the same breed can carry noticeably different chest depths, and a chart built around actual measurements only works if the measurement going into it is real.
Measuring More Than One Cat
Multi-cat households should measure each cat separately, since littermates and even twins can carry their weight differently across the chest. If you end up ordering more than one costume after measuring everyone in the house, a second costume gets an automatic 15% off at checkout, no code required — useful if your measuring session turns into an impromptu Halloween-planning afternoon.
What to Do Before You Order
Once you have your cat's chest measurement and have matched it to the right chart, order with shipping time in mind rather than waiting until the last week of October. The Bat Wings Pet Costume ships from our overseas facility, with 1–3 days of processing plus 7–14 days of delivery, so order it at least three weeks before Halloween to have it in time. The Pet Costume Hoodie, depending on the design, can ship faster — but either way, measuring early gives you room to exchange a size if your cat turns out to be between two charts, instead of scrambling the week of the party.
Frequently Asked Questions
How do I measure a cat for a costume if they won't stay still?
Measure right after a meal or during a calm, non-playtime moment, and have a treat ready at nose height. Most cats will hold still for the few seconds a chest measurement actually takes.
Should I measure my cat sitting down?
No. A seated or curled cat compresses its ribcage and will measure smaller than its true size, which is the most common cause of a too-tight costume. Always measure standing.
What if my cat's measurement is between two sizes?
Choose the larger size. That is the only case where sizing up is correct — never buy a size up in general to leave room to grow.