A stock keeping unit is the internal code you give one sellable variant, so a medium charcoal sock and a large charcoal sock are two SKUs even though they are one product. It is yours alone, unlike a GTIN or barcode, which identifies the same item across every retailer.

How should a SKU be structured?

Readable segments joined by a separator, ordered from broad to narrow: category, brand, then the attributes that vary, then a sequential number. Keep every segment a fixed width so codes line up when sorted, and start with a letter so spreadsheets never treat the code as a number.

How long should a SKU be?

Eight to sixteen characters suits most catalogues. Short codes collide once you pass a few hundred products, and codes past about thirty two characters get misread when warehouse staff read them aloud during a count.

Are duplicate SKUs actually a problem?

Yes. Two products sharing one code means their stock is counted as a single pool, so one sells out invisibly while the other appears in stock. This tool compares every generated code against the ones before it and names the row it collides with.

Should a SKU contain the price or the cost?

No. Prices change and costs are confidential, but a SKU is meant to stay fixed for the life of the product. Encoding either forces you to reissue codes, and a code printed on a shelf label should never leak a margin.

Is my product list uploaded anywhere?

No. Parsing and generation happen entirely in your browser using JavaScript. Nothing is sent to a server, which matters because a product list usually carries suppliers, costs and ranges you have not announced yet.

What file formats can I paste or upload?

CSV and TSV. Headers can be in any order and use the usual alternatives such as color for colour or vendor for brand. A file with no header row is read positionally as name, category, brand, size, colour.

Can I keep adding to the same scheme later?

Yes, as long as you keep the segment widths and the separator identical and set the sequence start to one past your highest existing number. Changing a segment width mid catalogue means old and new codes no longer sort together.

Do SKUs need to be unique across brands I sell?

Within your own systems, yes. Every code has to point at exactly one sellable variant. Including a brand segment is the usual way to keep two suppliers from producing the same code for different goods.

Can I use these codes as barcodes?

A SKU can be encoded in a Code 128 barcode for internal use, which is what most warehouse label printers do. Selling through retailers or on marketplaces additionally needs a GTIN, which is purchased from GS1 and is not something any generator can invent.

Free SKU Generator

Build SKU codes for a whole catalogue at once. Paste a product list or set the fields once, choose which segments the code contains, and get a table with every duplicate flagged. Nothing is uploaded to a server.

Free, no signup Runs in your browser Duplicates flagged

1. Add your products

A CSV or TSV list, or one set of fields repeated as a run.

2. Build the pattern

Each segment is shortened to the width you set. Turn one off and any two products that only differed by that field will now collide.

CategoryCharacters

Groups the catalogue so codes sort by department.

BrandCharacters

Keeps two suppliers from producing the same code.

SizeCharacters

Without it, every size of one product shares a code.

ColourCharacters

The other attribute that usually needs its own code.

Sequential number

StartDigits

The only segment that guarantees uniqueness. Pad to four digits or more so codes keep sorting correctly past 999 products.

Fixed prefix

Separator

Lowercase output

Pattern previewSOC-NOR-M-CHA-0001from Merino Crew Sock, Socks, Northbound, M, Charcoal

Codes ready? Next is the catalogue

A SKU is only useful once something is tracking it.

Grigora Commerce holds the catalogue, the variants and the orders on the same platform as your website and newsletter, so the codes you just generated stay attached to real stock instead of a spreadsheet nobody updates.

Start free Explore Commerce

How to generate SKU codes

Four steps from product list to a checked set of codes.

Add your products

Paste or upload a CSV with name, category, brand, size and colour columns, or switch to a single run and set the fields once.

Build the pattern

Pick which segments appear, how many characters each one takes, the separator, and the sequence padding.

Read the duplicates

Any code that repeats an earlier one is flagged with the row it collides with, along with codes that ran too long.

Copy or export

Copy every code as a plain list, or download a CSV with the SKU sitting next to the product it belongs to.

How to generate SKUs, step by step

Real screenshots of the tool, taken while building codes for seven products.

1
Paste your product list
One product per line, or a CSV with columns for category, brand, size and colour. Load the sample list to see the shape it expects.
2
Set the pattern once
Choose which attributes go into the code, how many characters each one contributes and the separator between them. Every row then follows the same scheme.
3
Copy or export the codes
Each code is checked against the others as it is built, so a duplicate is flagged here rather than discovered inside your inventory system.

When merchants use it

Six moments a generated scheme beats codes typed by hand.

Starting a catalogue from scratch

Set the scheme once at the beginning. Retrofitting SKUs onto a live catalogue means reprinting every label.

Adding a new season or range

Keep the existing segment widths so new codes sort next to the old ones in every export.

Moving off spreadsheet codes

Ad hoc codes typed by hand collide. Generating them from the same rules makes collisions visible.

Splitting a product into variants

One product with five sizes and three colours needs fifteen distinct codes, not one shared one.

Preparing a stocktake

Warehouse staff read codes aloud. Short, consistent codes cut the miscounts that follow from long ones.

Onboarding a supplier feed

Supplier codes rarely match yours. Generate your own and keep theirs in a separate column.

Exporting a product list from your platform

Where the file lives, by platform.

Shopify

Open Products, then Export, and choose CSV.
Keep the Title, Type, Vendor and Option columns.
Paste the file in above, then import the codes back into the Variant SKU column.

WooCommerce

Use Products, then Export.
Include Name, Categories and any attribute columns.
Generate here, then re-import matching on product ID.

Grigora Commerce

Open your product catalogue.
Export products as CSV.
Generate the codes and paste them back into the SKU field.

Manual spreadsheet

One variant per row, header in row one.
Name the columns name, category, brand, size, colour.
Save as CSV with UTF-8 encoding and paste it here.

Grigora vs. other SKU generators

Side by side.

Capability	Grigora	Web generators	Spreadsheet formulas	Inventory apps
Runs without upload	Yes, in your browser	Uploads your list	Uploads your list	Data lives in the account
Duplicate detection	Every code checked	Rarely	No	On save only
Custom segment widths	Per segment	Fixed	Fixed	Plan dependent
Bulk from a CSV	Yes, up to 5,000 rows	One at a time	Capped on free tier	Yes
Signup required	No	No	Yes	Yes

Common SKU mistakes and how to fix them

Eight problems that surface months after the codes are printed.

Two products share one SKU

Cause: The pattern leaves out the field that actually differs, usually size or colour.

Fix: Add the missing segment, or keep the sequence on so every row ends in a unique number.

Codes break in Excel

Cause: A numeric code like 0042 loses its leading zeros when the file opens.

Fix: Keep a letter prefix in the pattern. A code that starts with a letter is never read as a number.

Spaces inside the code

Cause: Category or colour values pasted in with spaces.

Fix: This tool strips spaces and punctuation already. Check the source data if a code looks wrong.

Codes too long to read out

Cause: Every segment set to five or six characters.

Fix: Three characters per segment is usually enough. Anything past thirty two gets misread on a shelf label.

Sequence restarts and overwrites

Cause: A second batch generated with the sequence starting at 1 again.

Fix: Set the start number to one past your current highest code before generating the next batch.

Slashes or hash marks in codes

Cause: A separator copied from an old scheme.

Fix: Use a hyphen, an underscore or nothing. Slashes break URLs and some barcode formats.

Padding runs out

Cause: Three digits of padding on a catalogue heading past 999 products.

Fix: Pad to four or five digits now. Widening it later changes every code you already printed.

Nothing generated for a row

Cause: The row is blank in every field the pattern uses.

Fix: Fill the source data, or enable the sequence so the row still gets a code it can be identified by.

Numbers worth fixing before you print labels

The constraints that decide whether a scheme survives growth.

Segments the builder can combine: prefix, category, brand, size, colour, plus a sequence

8-16

Character range that stays readable on a shelf label and in a spreadsheet

5,000

Rows this tool will process from a single pasted or uploaded list

Rows uploaded to a server by this tool

Frequently asked questions

Ten answers about SKU codes.

Related free tools

Other utilities that pair with the SKU Generator.

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