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LabelStack · fnsku label generator

FNSKU label generator

Amazon FNSKUs are not UPC numbers. They start with X, they encode as Code 128, and a typo reprints an entire inbound box. This page is the FNSKU-specific path: format checks, bulk CSV, and print-ready sheets, all in the browser.

  • Rejects values that do not look like an FNSKU (X + 8–20 alphanumeric).
  • Warns when length is not the common 10-character Amazon form.
  • Encodes as Code 128 with vector SVG bars — not a screenshot of a font.
  • Same Avery 5160-compatible 30-up sheet FBA sellers already buy.

Live press

Generate on this page

Template and symbology are pre-selected for this workflow. You can still change them. Nothing is uploaded.

1 Enter data · 2 Choose sheet · 3 Customize · 4 Export

Live press

Columns: value (required), symbology, name, sku, price, custom. Header row optional. Parsing stays on this device.

Sheet & fields

1" × 2.625", 3 × 10 on US Letter. Address / FBA 30-up.

Show on each label

If a whole sheet is shifted on your printer, nudge offset instead of stretching the PDF. Print at 100% scale, never “fit to page.”

Export

No watermark, no page cap. ZIP files use the current sticker size and include every field you turned on (name, SKU, price, custom) — not just the bars.

Add at least one valid barcode to export.

Paper & printer

This export is a Letter/A4 sheet. Have paper (and a laser) ready before you hit print.

As an Amazon Associate, LabelStack earns from qualifying purchases.

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Live sheet

Label layout is easier on a desktop, but you can still preview and export here.

Avery 5160 · 3×10 · page 1 of 1

Drag a label onto another to reorder before export. Print alignment uses this grid at the real page size.

What an FNSKU looks like

A typical merchant FNSKU is ten characters beginning with X, for example X001ABCDEF. Amazon assigns it when you convert a listing to fulfilled-by-Amazon (or when you share the catalog and need a unique sticker). It is not a check-digit GTIN. Treating it as EAN-13 will fail validation here on purpose. If you paste a 12-digit UPC into this mode, change the row’s symbology or use the bulk UPC page instead.

Why a dedicated FNSKU tool

Sellers search “FNSKU label generator” when they already know the code type and want to avoid a generic barcode site that defaults to Code 39 or a raster PNG. This page locks the default symbology to FNSKU, pre-selects the FBA 30-up template, and still lets you mix in other types per CSV row if a shipment file is messy.

Printing without covering the manufacturer code by accident

If Amazon requires you to cover the manufacturer barcode, place the FNSKU sticker directly over it. If not, leave the original GTIN visible and put the FNSKU on an adjacent face. Quiet zone (blank margin beside the bars) matters more than font choice — do not shrink the PDF to squeeze more labels onto a page.

A 1″ 5160 label can overlay many boxes. Poly bags and dark mailers need more height. Wrinkles and gloss are scan defects. Do not laminate inbound stickers. The FBA guide walks overlay, condition lines, and why a UPC in this column is the wrong job.

Format checks this page runs

FNSKU mode looks for an X-prefix and an alphanumeric body. It is not a GS1 check digit. A 12-digit UPC pasted here is flagged on purpose. Length around ten characters is common; longer Amazon forms exist and should still encode as Code 128. If a row is red, fix the cell before export. Including invalid rows is how a no-read sticker lands in a carton.

From the editors

Related guides

Questions

FAQ

Can I encode an FNSKU as UPC-A to save label width?

No. FNSKUs are alphanumeric and must be Code 128. UPC-A only accepts 12 digits. Forcing the wrong symbology produces a code that will not scan at the fulfillment center.

Do you store FNSKUs after I close the tab?

No. Rows live in memory for this session only. Preferences such as template choice can stay in localStorage; the actual FNSKU list is not written to disk unless you download a PDF or ZIP yourself.

Is my inventory/SKU data uploaded anywhere?

No. LabelStack runs entirely in your browser. CSV files, product names, SKUs, FNSKUs, and generated barcodes are parsed, validated, and rendered on your device. Nothing is posted to a server — there is no account and no backend that could store your catalog. You can confirm this in the network panel: generating and exporting never sends your rows anywhere. That is the point of the tool. Sellers who currently paste inventory into hosted generators are handing over supplier lists and Amazon FNSKUs; this site is built so we never see them.

What label sheet sizes are supported?

Presets include Avery 5160 (1" × 2.625", 30-up), Avery 5163 (2" × 4", 10-up), Avery 5167 (0.5" × 1.75", 80-up), plus 5161, 5162, 5164, 8160, Amazon FBA 30-up and 2×3 in, and A4 sizes L7160, L7163, and L7651. Each preset uses the published page size, label size, margins, and gutters so a desktop laser or inkjet lands on the actual sticker grid. If you use a house brand or a European size that is not listed, choose Custom size and enter width, height, columns, rows, and margins in inches. Letter vs A4 is a different page box — read the paper-size guide before printing a US PDF on A4 stock.

Is there a limit on how many barcodes I can generate?

No. There is no row cap, no page cap, and no watermark on PDF or ZIP exports. The only limit is your browser’s memory. Thousands of rows are parsed in chunks so the tab stays responsive; the sheet preview shows one page at a time while export walks the full set. If you generate tens of thousands of labels, leave the tab open until the PDF or ZIP finishes — it still never leaves your machine.

Why is this free?

LabelStack is a client-side tool with no servers to rent for your data. Optional advertisements on the page (never on the PDF, never over the download button) are how the lights stay on once the publisher network accepts the site. There is no paid tier because the product is the browser app: generate, layout, export. If ads are blocked, the generator still works. We also publish original guides because a tool without the print-alignment and symbology context is how people reprint a hundred bad stickers.