Clear answers to common barcode and Amazon FBA questions. No ticket queues, no bots. Just straight fixes you can apply right now.
Use this when you’re stuck between FNSKU, UPC, or EAN.
Common failure reasons at intake, plus fixes that actually work.
Thermal vs A4 sheet sizes, margins, and the “quiet zone” rule.
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If you’re in the warehouse and you just need the right next step, use one of these.
Need the proper breakdown (with a quick decision flow)? Read the full comparison. Still unsure? Run the Label Finder Wizard.
Code-128 is dense and reliable on smaller labels, especially thermal. That’s why Amazon’s FNSKU labels typically use it.
Yes, if you’re using FNSKU. If both are visible, Amazon’s system can scan the wrong one. That’s a common intake failure.
Printing at 95–97% changes bar width and can crush the quiet zone. Always print at 100% (Actual Size).
Thermal printers need correct driver size + solid bars (no dithering). A4 sheet labels need alignment and “Actual Size”.
Use this: How to Print FNSKU Labels.
The usual causes are faint bars, halftone/dithering, glare from tape, or a tight quiet zone. A quick test is scanning with your phone on the desk.
It depends on your printer. Thermal rolls commonly use sizes like 60Ă—30mm. A4 sheet labels vary (44-up, 21-up, etc).
Barcodes need clean white space around them. If the print goes too close to the edge, scanners can fail even when the data is correct.
Most rejections aren’t “wrong barcode”, they’re print quality and placement issues: glare, folds, smudge, visible UPC/EAN, missing 2D box content.
Anything that slows intake: unreadable labels, mixed barcodes, missing box content, or inconsistent placement. Prevent it with a 5-minute check.
These are the four “evergreen” pages that cover 90% of real-world issues.
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