Thermal shipping labels printing at the wrong size

You design a label that looks fine on screen, hit print, and the thermal roll comes out with text cut off, a barcode too small to scan, or a postage label that looks like someone shrunk it to 70%. Half the time the PDF is fine. The printer driver, the stock size, or the template millimetres are fighting each other.

I see this a lot on WooCommerce stores that print shipping and product labels in-house. Scale, stock mismatch and barcodes usually break first, long before the printer itself is at fault, and a proper label template often saves the day.

Start with actual size, not fit to page

Most wrong-size prints are the browser or the driver scaling the PDF. Print at 100% / actual size, turn off "fit to page", and match the paper size to the roll or sheet you loaded. A 100x150 mm label printed as A4 with fit-to-page will always look wrong.

Do one plain-paper test first. Mark the edges with a pencil against a real label. If the marks don't line up, fix scale and paper size before you burn through stock.

Template size has to match the stock

If the design is 4x6 inches and the roll is 100x150 mm, you are already off. Check the physical width and height on the template, not just how it looks in the editor. Millimetres are clearer than guessing from a screen preview.

Sheet labels need the same honesty. Rows, columns, gaps and margins have to fit the sheet. "Skip labels on first sheet" is useful when you are finishing a partly used sheet, but it will not fix a layout that is too wide for the page.

Barcodes and quiet space

A barcode that validates in the PDF can still fail on a thermal head if it is too dense or too close to the edge. Leave quiet space around Code128 and EAN codes, keep important text inside the label edge, and scan a physical sample before a batch. Tiny codes look clever in the designer and fail on the scanner.

Order data is a separate problem from size

Wrong address, missing SKU, or an empty field is not a print-scale issue. Bind live order fields carefully, set fallbacks where a value might be blank, and preview against a real order ID before you automate. Size problems and data problems get mixed up in support tickets, and they need different fixes.

When the PDF is right but nothing leaves the printer

Generating a PDF is not the same as a label physically printing. If you rely on emailing PDFs or staff downloading files, check mail delivery and who marks jobs printed. Direct PrintNode or desktop connector routing is a different setup again. Do not assume "PDF ready" means the courier label is on the parcel.

What I built for this

I kept hitting the same mess on client stores, so I built DawsonyWeb - Print Label Designer. Free covers the visual designer, live WooCommerce fields, barcodes and QR, and manual PDF generation on your own server. Pro adds automation rules, document history and email actions when you want labels to generate from order events.

It will not magically fix a driver set to fit-to-page. It does stop you rebuilding the same label in a spreadsheet every week, and it keeps template sizes in millimetres so the stock match is obvious.

If the store needs more than a template, I also do WooCommerce development for packing desks, courier integrations and the awkward bits plugins only half cover.

Try the label designer →

Most "wrong size" thermal labels are scale, stock mismatch or a barcode that was never scanned on paper. Fix those three before you buy another printer. Cheers.