Free SKU generator for Shopify products and variants

A SKU generator turns one naming rule into a stock keeping unit (SKU) code for every product variant, such as TSH-001-BLK-S for a black T-shirt in size S. This free SKU generator for Shopify builds those codes from the product type, a sequence number and the option values you choose, flags duplicates and risky characters, and gives you a CSV that Shopify can import. It can also fill the empty SKU cells in a product export from your store.

What is a SKU, and how is it different from a barcode?

In Shopify, a SKU is an optional code that identifies a product or variant within your business, in a format you choose. A barcode is an identifier for scanning: a custom value, or a number from a global registry such as a GTIN, UPC or EAN (Product details page). GS1 US describes a GTIN as a permanent number issued only by GS1, and a SKU as a code you create for your own inventory (GS1 US). A variant can have both. To print a barcode image from a code, use the Shopify barcode generator.

What makes a good SKU format?

Shopify’s SKU guidelines come down to a few rules; the tool checks the ones it can:

• One SKU per variant. A shirt in 3 sizes and 4 colors needs 12 SKUs. Shopify shows a warning in the Inventory section when it detects a duplicate.
• Letters, digits, hyphens and underscores. Shopify advises against spaces, special characters and symbols because they can cause search problems.
• No O/0 or I/1 mix-ups. Avoid formats where the digits 0 and 1 can be read as the letters O and I.
• Short. Shopify suggests no more than 16 characters; depending on your range, 4 to 8 can be enough.
• Consistent. If BLK means black on one product, it means black on every product. Keep one letter case too, because Shopify treats ABC123 and abc123 as different SKUs.
• Room to grow. Leave enough digits for the products you plan to add.

Spreadsheets add one more risk. Excel removes leading zeros and shows large numbers in scientific notation (Microsoft Support), so a digits-only SKU such as 00123 can change when the file is opened and saved. Including a letter avoids that.

How to use this SKU generator

1. In Build SKUs, enter each product’s title and up to three options with comma-separated values. The tool creates every combination.
2. Under SKU pattern, switch segments on or off and order them with the arrows. Give each an abbreviation rule: the first letters (Black → BLA), the first letter plus consonants (Black → BLC), initials, the whole value, or codes you type, such as BLK for Black.
3. Choose a separator and the sequence settings. Numbers can count products, every SKU, or restart within each product.
4. Fix anything flagged in the Checks column, then download the CSV or copy the SKUs.

How do I get the SKUs into Shopify?

• One variant at a time. In Shopify admin, go to Products and open the product. Click the variant in the Variants section, add the SKU in the Inventory section, then click Save.
• Bulk editor. Select the products, click Bulk edit, then add the SKU column from Columns. If saving fails with “Update the invalid values, then save again”, Shopify names a variant missing a required SKU and metafield validation errors as typical causes (Bulk editing). See how to fix Shopify metafield validation errors.
• New products by CSV. The download uses the column headers from Shopify’s product CSV template. Import it from Products > Import with Overwrite products with matching handles unselected, so Shopify ignores any product whose URL handle already exists (Importing products with a CSV file).
• Existing products by CSV. Export your products, switch to Fill SKUs in a Shopify export, upload the file, then import the updated file with overwrite selected. Overwrite replaces the store’s values in every column the file contains, and a blank cell in a non-required column clears that value, so import straight after exporting. The SKU columns only download leaves price and inventory out, which Shopify says keeps their current values, but includes Status, because Shopify uploads a product as active when that column is missing (Using CSV files). Import the one-product test file first, as the Shopify product CSV update checklist recommends.

What are the limits?

• Shopify allows up to 3 options and 2,048 variants per product (Adding variants). The tool refuses larger products and warns above 100 variants, which Shopify says some third-party themes and custom apps might not support.
• Duplicate checks cover only the products on this page or in the uploaded file.
• The fill mode needs a Shopify product export with a URL handle (or Handle) column and a SKU (or Variant SKU) column.
• A product CSV can’t exceed 15 MB, and an import can’t be cancelled once it starts.
• Add SKUs before you start selling. Shopify notes that SKUs added after an order was placed won’t appear in historical reports.