How to Add a Size Guide to Shopify Product Pages

November 6, 2026

Add the size guide as a modal or pop-up triggered from a link beside the size selector, with the table built from a metafield so each product shows its own measurements. A page link alone is not enough: most shoppers will not leave the product page and come back. The modal keeps them on the page and keeps the sale.

Where the guide has to live

Baymard's usability research has made this point for years: shoppers look for sizing information at the moment they choose a size, not before and not after. A link in the footer or a page in the navigation does not count, because the shopper is already on the product page with their finger on the selector. The guide has to be one tap away from the decision.

The practical answer is a modal. A small link reading Size guide sits beside the size selector, and tapping it opens a pop-up with the table, without leaving the product page. The shopper reads it, closes it, picks a size, and buys. Every extra page load in that flow costs you a percentage of buyers, and on mobile the cost is higher, because going back is a gesture people resent.

Build the table from metafields, not a page

The clean way to build this in a modern Online Store 2.0 theme is with metafields. Create a product metafield for the size table, fill it per product or per product type, and have the theme render it inside the modal. That way a jacket shows jacket measurements and a shoe shows foot length, instead of every product sharing one generic table that answers nobody's question.

The lazy version is a single size guide page linked from every product. It is better than nothing, but it forces the shopper to leave the product, read a table that covers five product types, find their row, and come back. Some will. Most will guess, and guessing is how you get a return. A return costs more than the ten minutes it takes to set up metafields.

What the table should actually say

A useful size table has three things: the measurement, the body it fits, and the unit. Chest in centimetres and inches, waist, hip, and length, with the size label in the first column. Add a line telling the shopper how to measure themselves, a tape around the fullest part of the chest, kept level, not pulled tight. That one line prevents more wrong sizes than any other sentence on the page.

Skip the model measurements as the main guide. A model who is six foot one and wears a medium tells the shopper nothing about their own body. Model info is fine as a footnote. The table is the guide. If your products run small or large compared to the standard, say so in plain words at the top of the modal: this brand runs one size small, size up. That sentence alone cuts returns.

Test it before you trust it

Once the modal is live, test it the way a customer would. Open a product on a phone, tap the size guide link, and count the taps to the answer. If it takes more than two, it is too slow. Check that the modal closes cleanly and the selected size is still selected when it closes, because a modal that resets the selector will cost you sales in a way no analytics report explains clearly.

Then watch the numbers for a month. The metric that matters is the return rate for wrong size, not the click rate on the guide. If wrong size returns drop and the guide gets used, it works. If the guide gets used and returns do not drop, the table is wrong, not the placement, and you need to measure the actual garments against the table.

Keep reading: Add Store Pickup Availability to Shopify Product Pages Without an App, Shopify Product Pages on Mobile: What Belongs Above the Add to Cart Button, and Add a Size Chart to Shopify Product Pages Without an App cover the nearby cases in this series.

Frequently asked questions

Should the size guide be a page or a pop-up?

A pop-up, triggered from a link beside the size selector. A page forces the shopper to leave the product and come back, and many will not. The pop-up keeps them on the product page, which is where the buying decision happens.

How do I show different size tables for different products?

Use product metafields. Create a metafield for the size table, fill it per product or per product type, and have the theme render it in the modal. That way jackets show jacket measurements and shoes show foot length, instead of every product sharing one generic table.

What measurements should a clothing size guide include?

Chest, waist, hip, and length, in both centimetres and inches, with the size label in the first column. Add one line explaining how to measure, a tape around the fullest part of the chest, kept level. Skip model measurements as the main guide.

Will a size guide reduce returns?

It reduces wrong size returns, which are usually the largest single reason for apparel returns. It will not fix returns caused by fit preference or quality issues. Measure the wrong size return rate before and after adding the guide to see the real effect.