The Size Guide
First things first. Get yourself a flexible tape measure, often referred to as a tailor’s measuring tape.
If you don't have one, no need to panic.
A regular retractable tape measure combined with a flexible cord such as a shoelace or belt will suffice.
Gently wrap the flexible measuring tape or cord around your pup’s neck, for larger dogs make sure to add 2 fingers to account for breathing room.
For smaller dogs 2 fingers could end up being too loose, if you have a little pup or tiny dog simply add 1 finger.
In case you used a cord; simply measure the length of the cord with the regular tape measure to find your number.
Now find the size in which your number fits comfortably.
Example: If your measurement is 40 cm, medium would be perfect. At 45 cm size Large would be a better fit.