Short answer: To add a size chart to Shopify without an app, put the chart on a page, create a product metafield that references a page, then add a Pop-up block to your product template and connect it to that metafield. Select the chart on each product. It's free and works on themes that support dynamic sources.
Picture a store that sells dresses, jeans and silk scarves. The owner adds a "Size chart" pop-up to the product template, and it looks right on the first dress. Then a shopper opens a scarf, taps "Size chart", and gets an empty box. Nothing is broken. That's how the built-in method behaves when a product has no chart selected, and it comes up again and again in Shopify Community threads about size charts.
This guide covers the built-in setup, how to give different products different charts, how to stop the empty pop-up, and when a size chart app is worth paying for.
Before you start: check your theme
The free method relies on dynamic sources, the theme editor feature that lets a block read a product's metafield. Shopify's tutorial says it requires a theme that supports them. On a vintage theme, you'd need to edit theme code or hire a Shopify Partner instead.
Two quick checks:
- Open the theme editor on a product template and click Add block. If you see Pop-up or Collapsible row, you're set.
- Some third-party themes name or structure blocks differently. One Shopify Community thread describes a theme with no Collapsible row at all, so look for your theme's own size chart or pop-up block before reaching for code.
Choose your setup by catalog
How much you build depends on how many different charts you need.
| Your catalog | What to build | Effort |
|---|---|---|
| One chart fits everything (a T-shirt brand) | One page, one metafield, select it on every product | Lowest |
| One chart per product type (dresses, jeans) | One page per type, same metafield, select the right page per product | Low |
| Some products need no chart (accessories) | Add a second product template without the pop-up | Low |
| Hundreds of products, charts assigned by rule | A size chart app | Monthly fee |
How to add a size chart to Shopify product pages
These steps follow Shopify's own tutorial, condensed. The menu names are from the desktop admin.
Step 1: Create the size chart page
In your Shopify admin, go to Online Store > Pages and click Add page. Name it after the chart, such as "Size chart: dresses", and add the measurements in Content. Set Visibility to Visible and save. Repeat for each chart you need.
Step 2: Create a page-reference metafield
Go to Settings > Metafields and metaobjects, click Products under metafield definitions, then Add definition. Name it "Size chart", click Select type, choose Page (one page is selected by default) and save.
Step 3: Add the Pop-up block to a product template
Go to Online Store, click Edit theme, and switch the top drop-down from Home page to Products. Shopify's tutorial creates a new template here with Create template, so you can apply the chart only to the products that need it (more on that below). In Product information, click Add block, choose Pop-up, and set the Link label to "Size chart". Next to Page, click the dynamic source icon and select your Size chart metafield. Save.
Prefer an accordion to a pop-up? Third-party walkthroughs show the same idea with a Collapsible row block whose content comes from the page.
Step 4: Select a chart on each product
Open a product, find Size chart in the Product metafields section, click Select pages, and choose the right chart. If you made a new template in Step 3, select it under Theme template. Save, then repeat for each product.
Stop the empty pop-up on products without a chart
Shopify's tutorial is direct about this: if a product uses the template but has no page selected, "the link text still displays as a link", and the pop-up opens blank. In a store that sells both sized clothing and one-size accessories, that empty box looks like a broken store.
The fix is the one a merchant posted after trying several answers in the Community: keep two product templates. The default template has no size chart block. The "size chart" template has it. Assign the size chart template only to products that need a chart. New products then start without the pop-up until you choose otherwise.
One more limit to plan around: a product can reference only one page. If a set needs a top chart and a bottom chart, put both tables on one page.
What to put in the chart
A chart in the right place still fails if shoppers can't read it.
- Say what you measured. Shopify's sizing guide separates body measurements (the shopper's bust, waist, hip) from garment measurements (the finished chest width or inseam). Label which one each column is, or shoppers compare the wrong numbers.
- Use a text table. A table reflows on a phone and can be zoomed without blur. A supplier's JPG chart often becomes unreadable on a small screen.
- Add a how-to-measure line above the table: where to put the tape for chest, waist and inseam.
- Show both units if you sell outside the US, and add a conversion row for US, UK and EU sizes if your customers ask for it.
- Keep one source of truth. Because every product points to the same page, fixing a number on the page fixes it everywhere.
When a size chart app is worth it
For a small catalog, the free method is usually enough. An app earns its fee when:
- You need charts assigned by rule, for example every product tagged "denim", instead of selecting a page on each product.
- You want a size recommender that suggests a size from the shopper's answers.
- You maintain many charts in several languages and want an editor with templates.
Prices and order-based charges vary a lot between sizing apps, so compare them before you install. Our Kiwi alternatives guide lists the main Shopify options with plan prices.
What a size chart can't tell a shopper
A chart answers "which size?" It doesn't answer "how will this look on me?" Both questions drive returns. In Loop Returns' data, fit or size is the reason for 56% of apparel returns, and style or preference for another 25%. The chart works on the first group. It can't do much about the second.
Visual tools work on the second question. Traion AI Virtual Try-On adds a Try Me button to your product pages: the shopper uploads or takes a photo and sees a generated preview of themselves wearing the item, without leaving the store. It doesn't measure anyone or recommend a size, so it sits next to your chart rather than replacing it. For how the two compare, see size charts vs. try-on. Traion is free to install with 10 free try-ons and no monthly fee, so you can install free and test it on your best-selling dresses first.
Set up the chart first, though. It costs nothing, and shoppers look for it on every sized product.