Online apparel return rates run between 20% and 40%, and fit is behind roughly half of them. A large part is “bracketing”: shoppers order two or three sizes on purpose, knowing they will send most of it back — a habit around 63% of them admit to.
A size chart does not fix everything, but it addresses the exact moment where the doubt appears: the product page, just before the add-to-cart. This guide covers the three ways to put one there on Shopify, what each really costs you in maintenance, and what separates a chart that reassures from one nobody opens.
Option 1 — Paste a table into the product description
The fastest route: build an HTML table in the product description editor and be done with it. It works, it costs nothing, and for a store with five products it may be all you need.
The cost shows up later. The table is duplicated in every product, so a single correction means editing every product by hand. It sits at the bottom of the description where few shoppers scroll, and HTML tables rarely survive a phone screen without horizontal scrolling.
Reasonable for a handful of products that share nothing. Painful past a dozen.
Option 2 — A metafield plus your theme
Shopify has native custom data. In Settings → Custom data → Products, create a metafield (a rich text one works well), fill it per product, then display it in your product template — Online Store 2.0 themes like Dawn can render a metafield through a block, no code required.
This is the cleanest no-app method: the content lives in Shopify, survives theme updates, and you keep full control. Its limit is repetition — you still fill the field product by product, and you get a static block: no popup, no unit switch, no size suggestion.
The right choice if you have a handful of charts and no budget.
Option 3 — Edit the theme code
With some Liquid, you can add a snippet to your product template that opens a modal, and read the chart from a metafield. It gives you the popup and the layout you want.
Two things to know before you start: the code lives in the theme, so switching themes means redoing it, and every theme update risks overwriting your file if you edited an existing one rather than adding your own.
Fine if you are comfortable in Liquid and rarely change theme.
Option 4 — A size chart app
An app is worth it once you stop wanting to touch products one by one. What you are buying is mainly the assignment logic: one chart applied to a whole collection, a tag, a vendor or a product type, so a new product inherits the right chart the day it is created.
Look at how the app renders on the storefront before anything else. Apps that inject an external script add a network request on every product page and can cost you Lighthouse points. Apps built on theme app extensions render inside your theme and add nothing at load time — and they uninstall cleanly, without leaving code behind.
What makes a size chart people actually use
- Real measurements, not just S/M/L — chest, waist, hips in centimetres or inches, ideally as ranges (88-93 cm rather than 90).
- A “how to measure” note or diagram: half the errors come from measuring the wrong place.
- International equivalences (EU, US, UK) if you sell abroad — a US shopper reading only EU sizes will guess, and guessing means a return.
- A cm/inch switch, so nobody has to convert in their head.
- It has to be one click from the size selector, not buried in a tab at the bottom of the page.
- On mobile: a table that scrolls sideways with the size column pinned, otherwise it is unreadable.
Going further: recommending the size instead of showing a table
A chart still asks the shopper to compare their own measurements with a grid. A size recommender does that comparison for them: two or three measurements in, one size out.
It is the same data — the ranges already in your chart — used differently. Done well, the calculation happens in the shopper's browser, which means no wait, and no personal measurements travelling to anyone's server.
Frequently asked questions
Does Shopify have a built-in size chart?
No. Shopify has no dedicated size chart feature. You can build one with a product metafield displayed in your theme, add a table to the product description, or use an app.
Do I need an app to add a size chart to Shopify?
No. A rich text metafield displayed through a theme block is enough for a few charts and costs nothing. An app becomes worthwhile when you want one chart applied automatically to a collection, a tag or a product type instead of filling a field product by product.
Where should the size chart appear on the product page?
Right next to the size selector, as a link or button opening a popup. That is where the doubt appears. A chart at the bottom of the description or inside a tab gets opened far less often.
Do size charts slow down my store?
It depends entirely on how the app is built. An app that injects an external script adds a network request to every product page. An app built as a theme app extension renders inside your theme and adds nothing at load time.
How much do size-related returns actually cost?
Apparel return rates run 20-40% online, and fit accounts for roughly half of them. Each return costs you the return shipping, the handling, and often the resale value of the item.
Return rate figures: industry benchmarks reported by Shopify and specialised return-management studies, 2025-2026.