Amazon FBA Barcode Generator

First decide which barcode this unit is supposed to carry

Almost everyone who arrives at a barcode generator has already skipped the decision that matters. Amazon does not ask you to print "a barcode" — it asks you to pick, per SKU, between two mutually exclusive schemes, and the label you print is just the consequence of that pick. In Seller Central the setting is called Amazon barcode versus Manufacturer barcode, and it lives on the individual listing, not on your account. Two SKUs in the same shipment can be set differently.

Choose Amazon barcode and Amazon issues an FNSKU — the X00… string this tool renders as Code 128. That code belongs to your listing and nobody else's. Every unit has to carry a physical FNSKU sticker, so there is real work per unit, and in exchange your inventory stays yours: the unit a customer receives is the unit you sent. Choose Manufacturer barcode and Amazon scans the UPC or EAN already printed on the retail packaging. No stickering, no label stock, no labour — but your units go into a commingled pool with every other seller's identical units, and a customer who buys from you may be shipped somebody else's stock. If that stock is counterfeit, damaged or an older revision, the complaint lands on your account.

If you resell other people's brands, the choice was probably made for you

This is the part that changed. As of July 2026, Amazon's FBA barcode documentation has commingling closed to resellers who are not enrolled in Brand Registry — the cut-off widely reported for that change was 31 March 2026. If that describes you, the stickerless option is gone: every FBA unit needs an FNSKU label even when the product already carries a perfectly good manufacturer UPC on the box. Brand owners enrolled in Brand Registry can still run stickerless on manufacturer barcodes, because there is only one legitimate source of that product and the counterfeit-mixing problem does not arise in the same way.

Read that alongside the other 2026 change and the practical picture is clear: Amazon ended its FBA prep and item-labelling services in the US on 1 January 2026. The old escape hatch — ship it in bare and pay Amazon a few cents a unit to label it — no longer exists there. Labelling is now your job, your factory's job, or a third-party prep centre's job, which means it has become a line in your landed cost rather than an FBA fee; if you are importing and rebuilding your unit economics around that, the way DDP quotes bundle prep and duty into a single per-unit number is worth reading before you accept a prep quote. Both of these are policy positions that move, so confirm them in Seller Central for your marketplace before you commit to a labelling workflow.

Now the physical label: what has to be true of the sticker itself

An FBA unit label is not just the barcode. Amazon's labelling guidance asks for a label carrying the scannable code, the product title and the item's condition, printed as Code 128 — which is why this tool renders FNSKUs in that symbology and not as a UPC-style numeric barcode. The other constraints are physical, and they are where home-printed labels usually fail:

• Size. Amazon asks for a label between roughly 1 × 2 in and 2 × 3 in. Of the presets in this tool, the Avery 5160 (2.625 × 1 in) and the 2 × 2 in square sit in or near that window. The 1.75 × 0.5 in and 1.75 × 0.667 in presets are below it and the 4 × 2 in is above it — they are here for internal SKU tags and case labels, not for FBA unit labels.
• Contrast and finish. Black bars on a white label, and the stock must be non-reflective. Glossy photo-label sheets are the classic mistake: a barcode scanner reads reflected light, and a gloss finish under the warehouse's overhead lighting throws a highlight straight back at the sensor. Matte stock, always.
• Adhesive. Removable adhesive is what Amazon asks for, so a returned or removed label does not destroy the retail packaging underneath.
• Quiet zones. The blank margin either side of the bars is part of the symbol, not decoration — a scanner uses it to find where the code starts and stops. This tool always exports ten modules of quiet zone on each side, which is why the "Fit to barcode" export is wider than the bars themselves. Roughly a quarter-inch of clear space is the figure usually quoted; do not crop into it to make a label fit.
• Resolution. Pick any label preset here and the PNG is composed at 300 pixels per inch — a 2.625 × 1 in label exports as 788 × 300 px. That 300 is a property of the file, not a setting on your printer, and the distinction trips up more people than it should; the pixels ÷ inches relationship behind it takes two minutes and saves a reprint. Keep the bar-width slider at 3 px or more: at 2 px the narrowest bar is a third of a millimetre on paper, and any ink spread at all closes it up.

One barcode per unit — everything else has to disappear

The single rule that causes the most avoidable damage is this one: when a unit is set to Amazon barcode, the FNSKU label must cover or obscure every other scannable barcode on the package. The manufacturer's UPC or EAN, an ISBN, a leftover courier label from the inbound freight, a distributor's own tracking sticker — all of them have to be gone or under the new label, so that exactly one code can be scanned. Sticking the FNSKU neatly in the empty space next to the UPC feels tidy and is precisely wrong.

It matters because receiving is automated and the scanner does not know which of two codes you meant. A unit whose manufacturer barcode is still readable can be received against the manufacturer's ASIN rather than yours, which is how sellers end up with inventory that shows as received somewhere in the network but not against the SKU they are trying to sell. Sorting that out is a Seller Support case and a reconciliation, not a click.

What actually happens when the label will not scan

Nothing dramatic and nothing fast — that is the problem. A unit with a smudged, cropped, glossy or duplicate-coded label cannot be identified on the receiving line, so it does not become sellable inventory on the day the truck arrives. It waits. Meanwhile your listing shows less stock than you shipped, your restock timing is wrong, and the discrepancy only surfaces when you reconcile the shipment and find units missing that are not missing at all. The cost is rarely the label; it is the two or three weeks of lost sell-through while nobody knows the stock exists.

Which is why the cheap checks are worth doing before a run. Print one label, scan it with a phone barcode app, and confirm the string that comes back is character-for-character the FNSKU you started with — this tool will happily render a typo into a perfectly scannable barcode of the wrong code, and so will Amazon's own label PDF if you feed it the wrong SKU. Then check the print at arm's length for ink bleed closing up the narrow bars. If you are setting up a listing from scratch rather than relabelling existing stock, the character and byte counts on the listing text itself are the other thing worth clearing before the shipment goes out, because a suppressed listing and a shelf of correctly labelled units is the same commercial outcome as a lost pallet.

Policy summary current as of July 2026. Amazon's barcode, prep and labelling requirements change and vary by marketplace — treat the above as orientation and confirm the specifics in Seller Central before printing a production run.

Frequently asked questions