1.Your baby usually wears size S doesn't mean all size S will fit him/her.
Different designers and manufacturers use their own size charts. So the measurements given in a size SMALL by manufacturer "A" will be a size XS in manufacturer B's size chart. Don't buy a particular size because that is what you always buy in a pet shop or online store. Always look at the size chart for chest girth and length and confirm the size before you commit to buy.
2.If any of the measurements are 'between' two sizes, choose the larger size.
If your measurements are toward the upper end of the range given for a particular size, you may also want to choose the larger size, as you may also wish to do for heavily coated dogs to accommodate all that fur.
3.Take each measurement a bit loosely.
Take each measurement a bit loosely, so there will be room for your dog to move and breathe, but not too loose. (the measurement for Belly Bands is the exception -- it needs to be a bit snug) Please measure carefully before buying and email us if you have any questions about fit before you bid or make a purchase.
Size Details:
Size XXS(Neck: 6inch Chest: 9.9inch Back: 5.9inch)
Size XS ( Neck: 7.8inch Chest: 11.8inch Back: 7.5inch )
Size S ( Neck: 9.4inch Chest: 13.8inch Back: 9.4inch )
Size M ( Neck: 11inch Chest: 15.7inch Back: 11.4inch )
Size L ( Neck: 12.6inch Chest: 17.7inch Back: 13.3inch )