A size guide is a helpful tool that provides measurements and fitting information for clothing, shoes, and accessories. It typically includes details like chest, waist, and hip measurements, as well as shoe sizes, to assist customers in selecting the right size. Size guides can vary between brands, so it's important to refer to the specific guide for each product. Many online retailers, including Amazon and Zappos, offer size guides on their websites. These guides often include a size chart that converts measurements into standard sizes, such as small, medium, large, or numerical sizes. Using a size guide can help reduce the chances of ordering items that do not fit properly.