Thermal label printer troubleshooting

By Omnia Toolbox · Updated 26 October 2026 · 7 min read

Thermal label printers are simple machines, so when one misbehaves the cause is usually one of a handful of settings. Find your symptom below. Each fix is listed in the order worth trying, quickest first.

The label prints tiny

The PDF is a full A4 or Letter page and the printer is shrinking the whole page to fit on a 4×6 sticker. This is what happens with Vinted labels and with many carrier websites' default downloads.

• Download a 4×6 version of the label if the platform offers one (eBay and Etsy do).
• If it doesn't, crop the label to 4×6 first. The label to 4×6 converter finds the label on the page and crops it without losing sharpness.
• Check the scale isn't set to "Fit to page" or "Shrink to fit".

A blank label comes out

• The printer printed the empty part of a full-size page. The label is in one corner of an A4/Letter PDF and the printer used a different corner. Crop the label to 4×6 first.
• The labels are upside down or the wrong type. Scratch the label with a fingernail: if the side facing the print head doesn't darken, the labels are loaded the wrong way round, or they're thermal transfer labels that need a ribbon.
• The print job went to another printer. Check the printer drop-down in the print dialog.

Labels skip, or one label prints across two stickers

The printer has lost track of where each label starts.

1. Recalibrate. Do this every time you load new labels. On most printers you hold the feed button until a few labels feed out; check your manual.
2. Check the paper size in the driver is 4×6, not Letter or A4. A Letter-sized job on 4×6 stock feeds roughly two labels per page.
3. Check the label guides are snug against the edges of the labels, so the stack feeds straight.
4. Clean the gap sensor with a dry cotton bud if calibration keeps failing.

The label prints sideways or cut off

• Set orientation to Auto or Portrait in the print dialog.
• If the PDF itself is a landscape page with the label rotated, the printer can't fix that. Converting the label to 4×6 straightens and rotates it so it fills the sticker.
• Check for a custom margin or "print header and footer" setting in your browser's print dialog and turn it off.

The print is faint, patchy or the barcode won't scan

• Increase darkness or density in the printer preferences or the printer's app.
• Clean the print head with an isopropyl alcohol wipe or a cotton bud. Dust and label adhesive build up on it over time, leaving thin white lines through the print.
• Use better labels. Very cheap labels can have an uneven thermal coating.
• Don't use a photo or screenshot of a label if you can avoid it. Use the original PDF so the barcode stays sharp.
• Store labels away from heat and sunlight. Direct thermal paper darkens with heat, and old labels can print grey all over.

The printer feeds labels non-stop

This usually means it can't detect the gaps. Recalibrate, check the labels are the gap type your printer expects (most 4×6 shipping labels are), and make sure the labels aren't loaded too loosely.

Nothing happens at all

• Check the printer is switched on, connected, and shows as ready (no flashing error light).
• Open the print queue and clear any stuck jobs, then print again.
• Reinstall the manufacturer's driver. Generic drivers installed automatically by the operating system cause many silent failures.
• On a phone, check you're printing through the printer brand's app if your printer needs one.

Still stuck?

If a label from a particular platform won't convert or print correctly, tell us which platform, carrier and printer you're using. We use reports like these to improve the converter. Please cover up names and addresses before sending any screenshots.