We have a mini dachshund and are looking to buy a dog flap for our back door.

How do you work out which would be the correct size dog flap for your dog. I don't just want to buy a small just in case it is to small.

Measure archies height from the ground to his wither (top of his shoulders)
This is the height the dog flap should be...

The width should be slightly wider than the widest part of his body (depending on his weight it will be either his belly or his shoulders/chest)

Does the 'small' size door you are looking at have measurements on it?