I took this from the site in my sig:
You can measure your dog for best fit. This will be fun! We promise. Measure your dog from the tip of their nose to where their tail starts and then again-we told you it would be fun-from either their head or shoulders down to the floor. Add a minimum of 3 inches to these measurements, depending on how your dog sleeps, so that they can stretch out, or let their cat friend join them...
You can measure your dog for best fit. This will be fun! We promise. Measure your dog from the tip of their nose to where their tail starts and then again-we told you it would be fun-from either their head or shoulders down to the floor. Add a minimum of 3 inches to these measurements, depending on how your dog sleeps, so that they can stretch out, or let their cat friend join them...