How to measure your cat for a harness (and pick the right size)
Most harness returns come down to one thing: the size was guessed from weight. Weight is a rough guide at best. A long, lean 4 kg cat and a compact 4 kg cat can need different sizes. Chest girth is what matters.
What you need
- A soft tape measure (a piece of string and a ruler also works)
- A calm cat, ideally after a meal or a play session
- A treat for afterwards
The two measurements
1. Chest girth. Wrap the tape around the widest part of the chest, just behind the front legs. Keep it snug but not tight: you should be able to slide two fingers underneath. Write the number down in centimeters.
2. Neck girth. Wrap the tape around the base of the neck where a collar would sit. Most vest-style cat harnesses only need chest girth, but the neck number tells you whether the top opening will be comfortable.
Reading the size chart
Every harness has its own chart, so always use the one on the product page rather than a generic size. For our Adjustable Cat Harness & Leash Set the chest ranges are:
| Size | Chest | Weight (guide only) |
|---|---|---|
| S | 29-33 cm / 11.4-13 in | 1.5-3 kg |
| M | 35-39 cm / 13.8-15.4 in | 3-4.5 kg |
| L | 40-44 cm / 15.7-17.3 in | 5-7 kg |
| XL | 45-50 cm / 17.7-19.7 in | 7.5-10 kg |
Match your chest number to the range. If your cat sits between two sizes, choose the larger one. Adjustable straps can take a harness in; they cannot make a small one bigger.
Checking the fit at home
- Put the harness on indoors, without the leash, and let your cat walk around for a few minutes.
- Two fingers should fit under every strap. More than that and a determined cat can back out; less and it will rub.
- Watch the front legs. The chest strap should sit behind them, not across the armpits.
- Kittens grow fast. Re-measure every month until they are around a year old.
A note on escape-proof claims
No harness is escape-proof, whatever the label says. A good fit, a few short indoor practice sessions and keeping the leash in your hand are what keep a cat safe. Never use a harness to tether a cat and walk away, and do not rely on it to prevent falls from balconies or windows.
Ready to measure? Start with the harness and leash collection.