Size XS: neck 30-38cm, width 2.0cm
Size S: neck 37-46cm, width 2.5cm
Size M: neck 40-50cm, width 3.0cm
Size L: neck 46-56cm, width 3.8cm
Measure the widest part of the neck, around the middle where the collar sits, and choose the size whose range your measurement sits inside, ideally near the middle. Measurements are taken by hand, and a difference of 1 to 2cm is normal. The ranges overlap, so if your dog sits in two sizes, the larger gives more room and a wider band. Once buckled, two fingers should slide flat between the collar and the neck. New leather is firm at first and softens over the first few weeks.