How to Add a Size Guide Popup to Magento 2 Product Pages

Ask anyone who runs an apparel or footwear store what drives returns, and "it didn't fit" is near the top of every list. Most of those returns aren't a product problem — they're a missing-information problem, and a size chart the shopper can actually find fixes a meaningful share of them.

Sizing ambiguity is a returns problem, not a support problem

A shopper choosing between "M" and "L" without a frame of reference — no brand-specific measurements, no conversion between US/UK/EU sizing — is guessing. Sometimes the guess is right. When it isn't, the item comes back, and the store eats the cost of a return that better information at the point of decision could have prevented. A size guide link placed right next to the size selector, showing an actual chart for that specific product category, closes that gap at the exact moment it matters — before the shopper adds to cart, not after the box arrives.

The reason this isn't already solved everywhere is that "add a size chart" tends to turn into either a static block hardcoded once and never updated, or a one-off template change every time a new category needs its own chart. Neither scales past a couple of categories.

How the module handles it

Size Guide gives an admin a grid for managing size guides — each one has a title and rich-text content, which is typically a size conversion table but can be any content that helps a shopper size themselves correctly. Each guide gets assigned to one or more categories: one guide for "Shoes," a different one for "Men's Shirts," and so on.

On the storefront, the product page automatically shows a size guide link if the product belongs to a category that has one assigned — and shows nothing at all if it doesn't. There's no manual per-product linking step and no risk of a shoe page showing a shirt-sizing chart, because the association lives at the category level and is resolved automatically.

Native, not bolted on. The popup itself uses Magento's own built-in modal component rather than a third-party lightbox library skinned to sort of match. That means it inherits the theme's actual modal behavior — animation, focus handling, close button — instead of looking and feeling like a plugin someone dropped in.

Manage size guides from an admin grid — title plus rich-text content, no template edits required.
Assign each guide to the categories it applies to; the correct one shows automatically per product.
No guide assigned to a category means no link shown — nothing irrelevant clutters the page.
Uses Magento's native modal component for a genuinely built-in feel.

Give shoppers the sizing confidence to buy right the first time.

Get Size Guide — free