Getting the right fit can be tough especially for a dog snowsuit with legs. Measuring your dog is the most accurate way to ensure the right fit! Whether you are measuring for a big or small dog snowsuit, the measurements we use are the chest girth (around the widest part of the chest) and the back length (from the collar to the base of the tail). In an ideal fit, the suit ends at the base of the tail and is not gaping in the chest, but it's okay for the suit to be a few inches short of the tail as long as your pup has a full range of motion. If your pup's measurements don't fit into one size, we recommend prioritizing the fit in the chest to ensure they're comfortable and to avoid accidents!