When taking measurements, use a flexible measuring tool such as a fabric tape measure. If you don't have one available, you can use a ruler and a ribbon or string. Mark the lengths on the ribbon and measure them on the ruler.
Find a flat surface for your dog to stand on. Have him or her stand straight with all four legs spaced normally under the body and head and tail up. Then determine the points on your dog that correspond to the points on the diagram above.
Take each measurement a bit loosely, so there will be room for your dog to move and breathe, but not too loose.
Dog collars are measured by the neck circumference of where the collar will sit. They should be snug not to slip over your dog's head but with enough room to fit two fingers between your dog's neck and the collar. Collars fitted too tightly can restrict breathing or cause coughing.
Most collars have adjustable lengths. It's best to go for a size where your dog's neck size sits in the middle. This allows you the room to alter accordingly. For puppies, choose a collar that can be adjusted as they grow. Be sure to check collar lengths regularly and often for puppies.
The width of the collar should be proportional to your dog's size. A collar with a width of at least 2.5cm is ideal for a large breed. A width of up to 2cm is suitable for a medium-sized dog. Around 1cm is best for a small or toy breed.
Dog clothes are generally measured by body length. Measure from the base of the neck (where the collar would sit) to the base of the tail along the dogs back bone.
Dog harnesses are measured by maximum chest circumference. This is the widest part of your dog's chest, usually just behind the front legs.
Your dog should have enough space on its bed to be able to lie flat down on its side with legs stretched out in front.