Shipping label size checker for A4, Letter, A6 and 4x6 PDFs
Upload a shipping-label PDF and see whether it is already ready for a 4x6 / 100x150mm thermal printer, or whether it needs a crop, resize or print-setting fix first.
Best for PDF labels from carrier, marketplace or shipping tools. If your file is a screenshot or image, check the PDF page size in your viewer instead.
Reads PDF page size
See the actual page dimensions in millimetres and inches instead of guessing from print preview.
Flags common formats
Detect 4x6, 100x150mm, A6, A4 and Letter sized pages, plus awkward custom layouts.
Shows the next fix
Get a plain-English recommendation for print settings, conversion or recurring workflow automation.
Why shipping label size matters before you print
A thermal printer can only print cleanly when the PDF page, the driver paper size and the label roll all match. If the PDF is A4 or Letter but the printer is loaded with 4x6 labels, the print dialog has to shrink, crop or rotate something.
That is why one seller gets a clean barcode while another gets a tiny label in the corner. The printer may be fine. The PDF may simply be the wrong page size for the stock in the printer.
Print settings to check after the PDF size result
- Set paper size to 4x6 inches or 100x150mm for most thermal shipping labels.
- Use actual size or 100% scale where possible.
- Avoid fit to page when the PDF is already 4x6.
- Use portrait or landscape based on the preview, not the label roll name.
- Calibrate the printer if the first label is correct but later labels drift.
When a shipping-label PDF needs conversion
If the checker says the PDF is A4 or Letter, do not send it straight to a 4x6 thermal printer and hope the browser fixes it. Use the free A4 to 4x6 shipping label converter for a one-off label.
If awkward PDFs keep coming from carrier, marketplace or shipping tools, LabelChop is the workflow upgrade. It watches your Downloads folder, detects shipping-label PDFs, crops or resizes them to 4x6 / 100x150mm and prints or saves the output automatically.
FAQ
What size should I print a shipping label?
Most thermal shipping-label printers use 4x6 inches or about 100x150mm. A4 and Letter PDFs usually need cropping or resizing first.
Does this tool store my PDF?
No. The checker reads the PDF page dimensions and returns the diagnosis. It does not save uploaded PDFs.
Can I use this for USPS, Royal Mail, eBay or Shopify labels?
Yes. It can check page sizes for PDFs from carrier and marketplace workflows, but LabelChop is not an official carrier integration.
What if my PDF is A4 or Letter?
Use a converter for a one-off file, or use LabelChop if awkward A4 or Letter label PDFs keep arriving in your Downloads folder.