Size Guide
Harness sizes
Measure the chest, not the weight. Two 10 lb cats can need different sizes. We sell M, L and XL.
| Size | Chest girth | Neck | Weight guide |
|---|---|---|---|
| M | 33 - 39 cm 13" - 15.4" |
28 - 32 cm 11" - 12.6" |
2.5 - 4 kg 5.5 - 9 lbs |
| L | 38 - 44 cm 15" - 17.3" |
30 - 35 cm 11.8" - 13.8" |
5 - 6 kg 11 - 13 lbs |
| XL | 40 - 46 cm 15.7" - 18.1" |
34 - 38 cm 13.4" - 15" |
6 - 7.5 kg 13 - 16.5 lbs |
Measurements are the actual outer diameter. Allow a 2-3 cm margin for manual measurement. Weight is a guide only, since cats of the same weight vary a lot in shape.
How to measure
- Chest: wrap a soft tape around the widest part of the ribcage, just behind the front legs. Snug, not tight - two fingers should slide under.
- Neck: at the base, where a collar would sit.
- Between sizes? Go up. A harness that is slightly loose can be tightened; one that is too small cannot be made bigger.
Long-haired cats: measure under the coat, not over it. Winter fur can add an inch that is not really there.
Buying a multi-pack?
You pick the colour and size for every single harness in the pack. Nothing arrives at random.
Not sure? Ask us first.
Email us the chest measurement and a side photo of your cat and we will tell you which size to order, before you spend anything. It takes us two minutes and saves you a return.
And if we get it wrong: do not ship it back. Tell us and we will send the right size. Wrong-size returns are our problem, not yours to pay for.
Carrier sizes
Both sizes expand the same way. The only question is whether you ever plan to fly.
| Size | Closed | Expanded width | Folded flat | Comfortable up to |
|---|---|---|---|---|
| Small | 16" x 10" x 10" | 26" | 2.76" | 13 lbs / 6 kg |
| Large | 18" x 12" x 12" | 32" | 2.76" | 20 lbs / 9 kg |
Which one do I need?
Choose Small if you ever fly. Delta, United and American publish an 18 x 11 x 11 inch under-seat limit, and American drops to 17.5 x 10.5 x 10.5 on Embraer jets.
Choose Large if you are not flying. More room for a bigger cat, for the car, the vet and home.
Airline under-seat limits
| Airline | Published limit |
|---|---|
| Delta | 18" x 11" x 11" |
| United (soft-sided) | 18" x 11" x 11" |
| American (single-aisle) | 18" x 11" x 11" |
| American (Embraer jets) | 17.5" x 10.5" x 10.5" |
| Southwest | 18.5" x 13.5" x 8.5-9.5" |
Published limits, verified August 2026. Airlines change policies and under-seat space varies by aircraft. Bulkhead and some window seats have less room, or none. Always check your flight before you book.