What this preflight catches
The label is buried in the corner of an A4 or Letter page.
A crop cuts into text, borders, or the barcode quiet zone.
The label is sideways or scaled to an unexpected aspect ratio.
The barcode cannot be decoded from the rendered 203 or 300 DPI output.
From source PDF to a print-ready label
Add the source PDF
Choose the exact PDF you plan to print. It is opened locally in your browser.
Review the detected crop
Drag the green boundary if the automatic crop misses any part of the label.
Download the corrected label
Export a 4×6, 100×150 mm, or A6 PDF and print it at Actual size.
Questions before you print
Does the checker upload my shipping label?
No. PDF rendering, crop detection, barcode decoding and export all run inside your browser.
Does a pass guarantee a carrier will scan it?
No. It is a software preflight, not ISO/IEC print-quality grading. Printer heat, media and hardware can still affect a physical label.
Can I use it without a thermal printer?
Yes. The tool creates a correctly sized PDF. You can inspect it now and test the physical print later.