Short answer
A size guide, also called a size chart, is a table on a product page that translates the store's sizes into measurements a shopper can check, such as chest, waist, inseam or foot length. Its job is to let someone choose the right size without holding the item.A chart of numbers is only half a guide. The useful half is the fit advice that sits around it: whether the style runs small or large, how it compares with the brand's other styles, what the model in the photo is wearing, and how the fabric behaves after washing. Shoppers rarely measure themselves. They compare with something they already own, which is why "I'm a medium in your crew neck, what about the hoodie?" is one of the most common pre-sale questions in apparel.
Guides break in predictable ways. One generic chart is used for every product, even styles that fit very differently. International sizes are converted inconsistently. Footwear widths are missing. And the guide lives in a theme file that support cannot see, so agents answer from memory and contradict the page.
| Part of the guide | Why it matters |
|---|---|
| Measurements per size | the baseline every answer starts from |
| How the style runs | stops the "true to size?" ticket |
| Comparison with other styles | matches how shoppers actually decide |
| Model's size and height | makes product photos useful for fit |
The weak approach is a single store-wide chart and an agent who answers fit questions from personal experience. Two agents give two different sizes for the same jacket, one of them is wrong, and the store pays for the return. Fit answers should come from the guide for that product, the same way every time.
Aide reads the fit guide a product page points to, including size charts stored in Shopify product metafields, and checks which sizes are in stock before it answers. A shopper asking how the hoodie compares with the crew neck gets an answer from both guides. If no written sizing guidance exists for a product, Aide says what it cannot answer and offers the team. More on using Shopify metafields and size charts in Aide.