This is how you calculate the leash length of a retriever leash
The specified leash length for a retriever leash always refers to the total length of the leash, from the end of the hand loop to the thimble, i.e. INCLUDING the collar (neck circumference).
In other words, it is best to measure the circumference of your pet's neck and then add the length that is most comfortable for you from the neck of your dog to the wrist strap.
In the following we have shown you how to calculate the line length you need: