Our sizing is based off of one metric - the length of your dog, from its collar to the base of its tail.
If your dog is still growing, in between sizes, or if the dog owner needs a bigger carrier to fit around his/her frame, consider a Booster Block to make sure your carrier fits not only the dog, but its owner properly.
Check out our instructional video below!
Find K9 Sport Sack Backpack Carriers that Fit your Dog's Size