Label NinjaGuides / thermal label printing
Label printing guides
Short, practical fixes for the labels sellers print every day: shipping labels that arrive as a full letter page, Whatnot labels that come out tiny, and the printer settings behind both. Each guide says what we checked ourselves and what is general guidance.
Shipping labels
Most marketplaces and carriers can hand you a letter-size page. These guides get the label onto a 4 × 6 roll at full size.
- Any carrierConvert an 8.5×11 shipping label to 4×6
Why Fit to page shrinks the barcode, and how to crop the label out of the page instead.
- eBayeBay shipping label not printing 4×6
Switch eBay's label format to 4 × 6 and fix a letter-size label you already paid for.
- Amazon returnsPrint an Amazon return label on 4×6
Save the full-page return label as a PDF, crop it to 4 × 6, or skip printing with a QR drop-off.
- Free toolShipping label to 4×6 converter
Crop a letter-size label PDF to a 4 × 6 page in your browser. The file is not uploaded.
Whatnot
Shipping labels from Whatnot, and the numbered item labels many sellers stick on stock before a show.
- TroubleshootingWhatnot labels printing too small
Change Whatnot's label size to 4 × 6, then match the printer's paper size and print at 100%.
- Free toolWhatnot number labels
Make numbered item labels as exact-size PDFs, and see how they differ from Whatnot Sorting Labels.
Printer setup
The same three settings decide every thermal print: the PDF page size, the printer's paper size and the scale. These sections cover them directly.
- Rollo, Zebra, MunbynWhere to set paper size on your printer
Windows, Mac and the common 4 × 6 printer drivers. General guidance, not a per-model test.
- SettingsThermal printer settings for a 4×6 PDF
Paper size, 100% scale, orientation, and what to do when the browser's PDF viewer ignores them.
- DiagnosisCropped, blank or sideways labels
Read the printed result: missing barcode, extra blank labels, or a label that feeds but stays blank.
About these guides: written by the Label Ninja team, an independent tool not affiliated with Whatnot, eBay, Amazon or any printer maker. Page sizes come from our own PDF output; marketplace menus and printer drivers change, so steps there are general guidance.