1.How to measure your dog? There is a picture to show how to measure your dog below,please check it.
2.Your baby usually wears size S doesn't mean all size S will fit him/her,please check the size information carefully before you buy.
You looked at one size chart and found that your dog is a size small. But that doesn't mean he/she is a size small for all the clothes. 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.
3.If any of the measurements are 'between' two sizes, choose the larger size.
4.If your pet dog is growing up,you can order a bigger size
5.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.