Each maker of dog accessories can develop their own sizing guide, there are no universal guides imposed for animal accessories.
This is the reason why it is so important to measure your dog instead of looking at the size label of your current collar/accessory.
Q: How do I measure dog's neck to pick the right size?
A: Wrap a tape measure around the spot a collar usually sits at - different breeds can have it higher or lower than others. Make the tape measure snug and loosen it up only to fit two fingers under it. That's the measurement you'll need to pick correct collar size. If your measurement is right on the size edge, pick the size up or down, OR request the size alternation in your order note- it is free to add or take some length. NEVER pick a size that is just right - mind that very furry breeds will have thick layer of fur trapped under the collar- making the needed size substantially larger.
Size chart for our 40mm and 50mm collars:
M: 37-43cm / 14.5 - 17 inches
L: 42-50cm / 16.5 - 20 inches
XL: 46-60cm / 18 - 23.5 inches
XXL: 50-68cm / 20 - 27 inches
Collars without the handle can be shortened more than what shows in the chart- up to 3 cm- depending on size and model. Flat collars without patch area - up to 6cm smaller. The maximum size stays the same in all models.
Size chart for our Mini Tactical 25mm collars:
S: 28-36 cm / 11-14 inch
M: 34-44 cm / 13.4-17.3 inch
L: 39-54 cm / 15.3-21 inch
Size chart for our puppy and flat 25mm collars:
S: 22 cm - 28 cm / 8.7 inch - 11 inch
M: 26 cm - 39 cm / 10.2 inch - 15.3 inch
L: 32 cm - 47 cm / 12.5 inch - 18.5 inch
Each item has it's sizing guide added to the description.
Our size charts show the dog's neck the collars fit on, not the actual spread of the collar - we keep a small buffor at each size end, however it varies from collar to collar and isn't guaranteed.