If you are selling products that have different sizes (e.g. clothing), it's critical to provide users with size charts. If shoppers are not sure if it's the right size for them, they will have a lot of hesitation in purchasing process.
But there can be another problem: if it doesn't fit to them, they will want to return it and get refund or exchange it, which will negatively impact on their purchasing experience from your website. That's why you must have size charts for products where sizes matters:
Good example from Shapermint:That is the product page for leggings, and for such product it's very important to buy relevant size. That's why they have "Use our sizing chart" text below size selector.
- It will simplify decision-making process and remove fears about purchasing a wrong size;
- It will decrease returns;
- It will decrease refunds.
If users are not sure which size to choose, they can get recommendation there. Moreover, they have "Free Exchange" badge below ATC button, which is another thing related to size: if the size doesn't fit to you, you can exchange it for free.