How to print shipping labels on a thermal printer
A 4×6 thermal label printer is the single biggest time-saver for anyone shipping more than a few parcels a week. No ink, no scissors, no tape over the barcode: the label comes out as a sticker and goes straight on the parcel. Getting the first label to print properly is where most people get stuck, though. This guide walks through the whole setup, from buying labels to printing from your phone, and explains what to do with platforms like Vinted that don't give you a 4×6 label at all.
1. Buy the right labels
Thermal shipping printers use direct thermal labels. There's no ink or ribbon: the printer heats the paper and it turns black. When shopping, check three things:
- Size: 4×6 inches (sold in Europe as 100×150 mm or "A6"). This is the standard courier label size used by Royal Mail, Evri, InPost, DPD, USPS, UPS and FedEx. 100×150 mm and 4×6 in are close enough to be interchangeable.
- Fanfold or roll. Fanfold stacks (usually 500 labels) sit behind the printer and feed through a slot. Rolls need a holder that fits your printer's core size. Fanfold is usually cheaper per label and jams less.
- Direct thermal, not thermal transfer. Thermal transfer labels need a ribbon, which home shipping printers don't use. If a label won't print at all, check you didn't buy the wrong type.
Quick test: scratch the label with a fingernail. Direct thermal paper leaves a dark mark.
2. Install the printer driver
On a computer, always install the manufacturer's own driver (Rollo, Munbyn, Zebra, Phomemo, iDprt, Jadens and so on) rather than relying on a generic driver that Windows or macOS picks automatically. The generic one often doesn't know about 4×6 paper, which leads to labels that print on half the sticker or skip every other label.
- Download the driver from the printer brand's official support page, not from a third-party download site.
- Connect the printer by USB (or Wi-Fi/Bluetooth if your model supports it) and run the installer.
- Open your printer list and print a test page from the printer's properties. If the test page comes out on one label, the driver is working.
3. Set the paper size to 4×6
This is the setting that causes most problems. In the printer's Printing preferences (Windows) or the print dialog's paper size menu (macOS), choose 4×6 in or 100×150 mm. If it isn't listed, add a custom paper size of 4 × 6 inches (101.6 × 152.4 mm) and select it. Make it the default for that printer so you don't have to pick it every time.
4. Calibrate
Calibration teaches the printer where one label ends and the next begins, using the gap or black mark between them. Run it when you first set up the printer and every time you load a new stack or roll. Most printers calibrate by holding the feed button for a couple of seconds until a few blank labels feed out; Rollo printers calibrate automatically when paper is loaded. Your printer's manual will show the exact method.
Labels skipping or printing across two stickers? It's almost always calibration or the paper size setting. See thermal printer troubleshooting for the full list of fixes.
5. Get a 4×6 label from each platform
The printer can only print a 4×6 label properly if the PDF you send it is 4×6. Marketplaces handle this differently:
| Platform | Label format | What to do |
|---|---|---|
| eBay | Choice of formats | Pick the 4×6 / label printer option in the label printing settings. |
| Etsy | Choice of formats | Choose the 4×6 label printer format when downloading. |
| Poshmark (US) | 4×6 PDF | Print directly at 100% scale. |
| Vinted | Full A4 or US Letter page only | Convert it first with the Vinted label to 4×6 converter. |
| Carrier websites (Royal Mail, Evri, USPS, etc.) | Often A4/Letter by default, sometimes with a 4×6 option | Look for a "label printer" or "6×4" setting before you download. |
Platforms change their label options from time to time. If the setting has moved, look for words like "label printer", "thermal" or "4×6" in the shipping or print settings.
When a platform only gives you a full-page PDF, the label usually sits in one corner of the page surrounded by white space. Sending that page to a thermal printer makes it shrink the whole page down to 4×6, so the label comes out tiny and the barcode may not scan. Cropping the label out of the page first fixes it, which is what our converter does automatically, without uploading the label anywhere.
6. Print at 100% scale
In the print dialog, set:
- Printer: your thermal printer (PDF viewers often default to your last-used printer).
- Paper size: 4×6 in / 100×150 mm.
- Scale: 100% or "Actual size". Never "Fit to page" or "Shrink oversized pages".
- Orientation: Auto or Portrait.
Printing from Chrome or Edge? The browser's own print preview has a "More settings" section with paper size and scale; check both there too.
7. Printing from a phone
Most budget Bluetooth printers (Phomemo, Munbyn, iDprt and similar) print from the manufacturer's app rather than the phone's built-in print menu. The usual flow:
- Download the label PDF from the marketplace app.
- If it's a full-page PDF, convert it to 4×6 first. Our converter works in your phone's browser.
- Open the 4×6 PDF, tap Share, and choose the printer's app.
- In the app, set the label size to 100×150 mm and print.
Wi-Fi printers that support AirPrint or Mopria can print straight from the phone's print menu. Choose the 4×6 paper size there.
Do you actually need a thermal printer?
If you ship a handful of parcels a month, probably not. Printing two labels per page on half-sheet sticker paper works fine. Once you're shipping several orders a week, the time saved and the lower cost per label add up quickly. We compare the numbers in thermal vs inkjet: the real cost per label.