Choose a test that answers the printing question
Print a sample locally before you buy postage. A printer's built-in test checks the device. A correctly sized test file checks the computer or phone, printer queue, loaded stock and print dialog together. Use plain text such as TEST PRINT – NO POSTAGE, with simple marks for scale and alignment. Leave out names, addresses, carrier marks and barcodes. Keep the sample away from parcels you intend to send.
| What you want to check | Use this test | What the result tells you |
|---|---|---|
| Does the printer feed and mark stock? | The manufacturer's supported self-test or a documented feed check followed by a simple label | Whether stock advances and whether the print is visible. |
| Does this computer or phone reach the printer? | One short label from the intended app and printer queue | Whether that device, queue and connection send a job successfully. |
| Will the label stay in the right position on the stock? | A single PDF or label document matching the loaded dimensions | Whether orientation, print scale, margins and feed line up. |
| Does an A4 sheet line up with its label panel? | An A4 plain-paper print overlaid on an unprinted sheet | Whether the selected panel and page position match the sheet. |
Make a plain test label in the exact size
- Measure one unused label, including its width across the printhead and length in the feed direction. Check the printer's documentation for supported dimensions and media. If you use an A4 sheet, use an A4 page and place the test content inside the actual label panel.
- In your label editor or an app that lets you set a custom page size, start a one-page document at those dimensions. Set the intended orientation and type TEST PRINT – NO POSTAGE in large plain text.
- Add a short straight line of a known length, such as 50 mm, and a few small marks well inside the printable area. The line helps check scale and the other marks help check placement. Keep the layout to ordinary text and lines.
- Save or export as PDF if your app supports it and you expect to print carrier PDFs through a PDF viewer. Check the resulting page dimensions before printing. If your workflow only prints from a label app, save a matching design in that app and use it as a connection and feed test.
Measure the stock instead of relying on the shorthand 4 × 6. Exact 4 × 6 inches is 101.6 × 152.4 mm. A common open-format label measures 100 × 150 mm. Brother DK and other model-specific stock can have different dimensions and loading systems. 4 × 6 versus A4 shipping label guide
The MUNBYN fanfold pack below measures 101.6 × 152.4 mm. Use it as an example only if your direct thermal printer accepts external fanfold media at that size and the print driver offers the matching setting. Brother DK printers require their own supported media. MUNBYN UK shipping labels
Open-format fanfold supply
MUNBYN 4 × 6 inch fanfold shipping labels
A 500-label fanfold pack for compatible direct thermal shipping printers. The folded stack sits behind the printer and feeds without putting a large roll inside the machine.
Keep in mind. Check the actual printer’s width, gap sensing and feed instructions. These open-format labels are a different system from Brother DK holders and DYMO’s Series 5 authenticated rolls.
- 4 × 6 inch format
- 500 fanfold labels
- Direct thermal media
Print one copy and measure it before changing settings
Load the stock and follow the printer maker's normal media setup. In the print dialog select the correct printer queue, paper size and orientation. Start with one copy. For a matching test PDF, choose Actual Size or 100% where the viewer offers it. That setting keeps the page scale, but it can still clip content outside the printable area. Check the preview before printing. Adobe guidance on scaling a PDF
Measure the line on the print with a ruler. If a 50 mm line comes out smaller, inspect print scaling and paper settings before changing your layout. If the line is the right length but the whole print is offset, check orientation, guides and margins. If an extra blank follows each label, check the physical label length, document page count and feed setup. Thermal labels printing at the wrong size · Thermal printer skips labels
For A4 self-adhesive sheets, first print on ordinary A4 paper using the intended orientation and tray. Hold the test and label sheet together against the light. Check the printed marks sit inside the expected panel before feeding the adhesive sheet. This helps catch a wrong page position while the label sheet is still unused. A4 postage labels on self-adhesive sheets
Check the genuine postage file before dispatch
The test shows how your printer handles one local file. Buy or generate genuine postage through the carrier or marketplace when you are ready to send the parcel, then check the actual file and service instructions. A generated label can include a different page size or extra paperwork. Print the intended page using the provider's settings, and check that the whole label and barcode appear without clipping or distortion. Royal Mail warns that resizing its Click & Drop labels can affect barcode scanning. Royal Mail label formats · Royal Mail print guidance
If you use Click & Drop Desktop, Royal Mail documents a Test Auto Print connections action for checking the application connection. Use the correctly sized local print to check feed, placement and scale as well. Keep one real label with the correct parcel and discard the marked test. Royal Mail Click & Drop Auto Print guidance
Printing and carrier sources
Common questions
Do I have to buy postage to test my label printer?
You can send a local non-postage sample to test connection, feed, size and alignment. Use a genuine label from the carrier or marketplace for dispatch.
What should I put on a shipping label test print?
Use the words TEST PRINT – NO POSTAGE, a short line of known length and simple alignment marks. Leave out addresses, carrier logos and barcodes.
What page size should I use for a 4 × 6 thermal label test?
Use the actual supported dimensions of your stock. Exact 4 × 6 inches is 101.6 × 152.4 mm. A 100 × 150 mm label or a Brother DK format can need a different setting.
Can a printer’s self-test tell me if a postage PDF will print correctly?
The self-test can check the printer and media. Use a matching file from the app and queue you intend to use to check placement and scaling, then check the genuine PDF separately.
How do I check an A4 label sheet without using an adhesive sheet?
Print the test on plain A4 paper first. Hold it against the unused label sheet and check that the marks line up inside the expected label panel.