Using a tape measure (or a piece of string that you measure on a flat ruler later), take the measurements below while your cat is standing up. Remember to draw the tape measure tight enough to compress any fur underneath!
Small - Chest: 24-28cm, Neck:20-24cm
Medium - Chest: 28-32cm, Neck:24-28cm
Large - Chest: 32-36cm, Neck:28-30cm
XL - Chest: 40-46cm, Neck:34-38cm
XXL - Chest: 46-59cm, Neck:36-42cm
XXXL - Chest: 59-65cm, Neck:49-56cm