In order to ensure a proper fit of your collar, use the following method to measure your neck size …
1) Take a string or cord and wrap it around your neck. Make it snug, but not too tight.
1a) Alternatively use a tailor’s cloth measuring tape and skip steps 2 and 3
2) Get a pen and mark the point on both sides where the string overlaps
3) Lay the string flat and measure the distance between the two points that you marked.
4) Add 12mm (½") to the measured size for comfort
5) The resulting measurement is your correct size