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shopify / metafields / product-pages

Shopify Metafields: Where They Show and How to Add One

By StoreKitly

A Shopify metafield is a typed field with a place on the product page. Use it for size charts, care notes, and specs, and connect it to a theme block.

A Shopify metafield is a custom field attached to a product, variant, collection, customer, or order. It gives a reusable fact—a size chart, care instructions, a list of materials—its own place in the admin and, once connected to a theme block, its own place on the storefront. The value stays invisible to shoppers until you make that connection.

Quick answer

  • A metafield needs three things: a definition, a value, and a theme connection.
  • Use metafields for facts you reuse; use variant options for choices that change the cart.
  • A Page or metaobject reference is best for a chart shared by many products.
  • Only some metafield types can become filters in Search & Discovery.
  • Without the theme connection, the value remains in the admin.

Description, option, or metafield

The product description is for copy that sells. It is a bad place for a fact you need to reuse, compare, or filter. The product title has its own SEO job — see Shopify product title SEO.

Information Where it goes Why
The pitch, story, use cases Product description Free text written for one product
Size or color the shopper picks Variant option It changes the variant added to the cart
Size chart, care guide, assembly PDF Metafield Shared by many products and shown in its own block
Dimensions, weight, material Metafield with a matching type Typed values, and some types can become filters

Variant options are not metafields. If a product has too many variants to manage cleanly, see Shopify variant limit.

Set the product’s category before creating a custom field. Many categories already include metafields such as size, fabric, color, and sleeve length. If the category has the field, use it instead of building a duplicate.

Create a size chart metafield

Say you sell tops in three fit groups across forty products. Each group has one chart, and every product in that group uses the same chart.

1. Choose a shared reference or per-product text

Forty products and three charts means a reference, not a copy. If you paste the chart into a rich text field on every product, the next measurement fix is forty edits.

Type What the product stores Good fit
Page reference A link to a store page holding the chart Shared charts edited in the page editor
Metaobject reference A structured entry with a table, image, and fit note Charts that need the same fields every time
Rich text The chart itself, per product Products whose charts are truly unique
File An image of the chart A quick start, with ALT text managed separately

For three shared charts, a Page reference is the simplest route. Choose a metaobject when every chart must have the same parts, so nobody forgets the measuring image on chart number seven.

2. Use one value

Make it a product metafield with one value. One chart per product is the normal case. Choose List of values only when a product genuinely needs two charts, such as a top and bottom sold as a set.

3. Connect it to a theme block

In the page-reference route, add a Pop-up block to the product information section and connect its page setting to the metafield with the dynamic source icon. Shoppers see a “Size chart” link that opens the page content.

There is a catch: if a product uses that template but has no page in the metafield, the link still shows and the pop-up opens blank. Shopify Help’s fix is a separate product template for products with charts, and the normal template for everything else. Assign the chart template only to products that need it.

With a metaobject, connect the fields through the product’s metaobject reference. The theme decides which blocks are available, so check its documentation before you design the fields.

4. Do not make the chart a filter

A page reference is not a filterable type, and shoppers do not filter by “which chart.” They filter by size, which is already a variant option. The chart explains the sizes; the option is what they select.

Care instructions and specs

Care instructions are the easiest case. In Shopify Help’s care instructions tutorial, typing “Care guide” as the definition name brings up a standard definition. The value shows in a Collapsible row block connected to the metafield.

Care instructions display only on products that have a value, so one default template can serve every product. That is not true of the size-chart pop-up above. When a feature appears on the wrong products, check which block type it uses first.

For anything with a unit, use a measurement type. Help lists Dimension, Weight, Volume, and others, each storing a number plus a unit. A few rules keep specs maintainable:

  • One metafield per spec a shopper would compare. “Width” and “Seat height” as separate fields beat one “Dimensions” text blob.
  • Be careful with JSON spec tables. JSON is an advanced type; check your theme’s supported dynamic sources before relying on it.
  • Several specs in one block. When the dynamic source icon shows a +, you can connect more than one metafield to the same block.

Turn metafields into filters

The Search & Discovery app builds storefront filters from options, metafields, and metaobjects. For how those filters change collection pages, see Shopify collection SEO. Only these metafield types can be filter sources:

  • Single line text, and Single line text (List)
  • Decimal
  • Integer
  • True or false
  • Metaobject reference, and Metaobject reference (List)

That list settles some type choices before you fill in forty products:

  • Rich text, multi-line text, page, and file metafields are not filterable. Fine for size charts and care; a problem if you stored “Material” as a paragraph.
  • Measurement types are not filterable. If shoppers need to filter by a number, store it as Decimal or Integer.
  • Use preset choices for text you plan to filter. Otherwise “Cotton,” “cotton,” and “100% cotton” become three values.

Help also notes a store can have up to 25 filters, a collection with more than 5,000 products does not display filters, and a single filter shows at most 100 values.

Common mistakes

  1. Creating a definition but no value. The field exists, but this product has nothing in it.
  2. Connecting the block on the wrong template. A connection made on one product template does not apply to another.
  3. Using a type the theme cannot render. Check the theme’s supported dynamic sources before filling forty products.
  4. Using rich text for something shoppers must filter. Rich text is not a filter source.
  5. Forgetting the empty-pop-up case. A product with the chart template but no page shows a link that opens blank.

FAQ

What is a product metafield in Shopify?

A custom field on products, defined once and filled in per product, such as Care guide, Size chart, or Material. Shoppers see it only after you connect it to a theme block with a dynamic source or display it with theme code.

Do I need an app to add a size chart?

Not for Shopify Help’s route. A Page-type product metafield, a page holding the chart, and a Pop-up block are enough if your theme supports dynamic sources. Older themes need theme code or a developer.

Why isn’t my metafield showing on the product page?

Check the three steps in order: the definition exists, this product has a value, and a block in this product’s template is connected to it. If the product uses a different template, the connection elsewhere does not apply.

Can customers filter products by a metafield?

Yes, through Search & Discovery, but only for single line text, decimal, integer, true or false, and metaobject reference fields, plus their list versions. The theme also has to support filters.

Where do I manage metafield definitions?

Most Shopify Help pages now say Settings → Metafields and metaobjects. Some older pages still call it Settings → Custom data. You can also add a definition from a product’s Metafields section.

Sources