Choosing the Right LupinePet® Collar for your Dog
First, measure your dog's neck. The best way to get the correct size is to measure your pet.
A soft tape measure is easiest. A piece of string or a belt can also be used and then measured against a ruler, or even estimated against a known length, like a sheet of paper (A4 or A5 for example)

'Add 2 inches' is not an accurate way to estimate the size needed. Two inches is a lot to a small dog, but may not be enough for a big dog.
Measure snug against the fur, then add about 5% more to the total.
Keep it simple by rounding the initial measurement up to the next whole number if it is over 1/2", or round down if it is less than 1/2".
Estimating Example: Dog’s actual inches around the neck = 17"
10% of this measurement would be 1.7", or about 1-and-3/4", of which half (the 5%) is about 1 inch, with a bit of rounding up.
This pet would need a collar adjusted to a length of about 18".
Next, choose the width of the material:1/2" wide for small dogs up to 20 lbs (approx 10kg) . A standard wire staple for
holding papers or magazine pages is 1/2" wide.
3/4" wide is safe and comfortable for many sizes of dogs.
1" wide is sometimes preferred for being more visible. It can also spread pressure over a wider area, so it may be more comfortable for a hard puller. It can be bulky on smaller dogs, especially when adjusted to its smallest.
Now that you have a length and width, you're ready to shop!
We make two types of dog collars:
Adjustable collar: The standard flat collar. Best for all-the-time use. Measure around the middle of the dog’s neck. Add 5% more.
Martingale collar: Used to prevent a dog from 'backing out' of its collar, the 'martingale' is a loop of webbing within the collar. When your lead is attached to this, tension on the lead will cause the collar to tighten a limited amount. Without tension, the collar resumes its normal adjusted size. A second D-ring sewn into the collar does not change the size of the collar giving the option of using the martingale or not. In 3/4" and 1" widths only.
This collar does not have a buckle. Measure the dog’s neck as well as all the way around the head to be sure the collar can be slipped on and off over the head. Add 5% to the larger of the two measurements and use that to choose the size range. Due to a somewhat higher risk of entanglement, this type of collar should not be left on an unattended or unleashed dog.