Frequently Asked Questions

No. Everything runs locally in your browser using JavaScript. Your file never leaves your device — there is no upload, no account, and nothing to delete afterwards. That's also why the tool works offline once the page has loaded.

Yes. The crop box is scaled to fit inside the 4×6 page — never stretched — rendered at 200 DPI, and centered on a white background. Print at 100% scale with paper size set to 4×6 in (101.6×152.4 mm) and the barcode keeps the exact proportions the scanner expects.

Yes. Each page gets its own auto-detected crop box that you can adjust individually. If every page has the same layout, use "Copy this crop to all pages" and you're done in one click.

Yes. Any carrier or marketplace label saved as a PDF works. The tool finds the label area visually (the non-white bounding box) instead of depending on a specific layout, so unusual formats are fine — and if auto-detect misses, you can drag the box manually.

4×6 in (101.6×152.4 mm) is the standard label size for thermal shipping printers such as Rollo, Dymo and Munbyn. (Some drivers list it as 100×150 mm — a slightly smaller, near-equivalent size — and the tool can export that size too: pick it in the Output size selector before downloading.) Printing an A4 or Letter PDF on 4×6 stock without cropping is exactly what causes tiny, cut-off, or unscannable labels.

Free forever, no watermark, no sign-up, no usage limits. That is the point — several competing tools watermark their free conversions. This one doesn't, because your file never even reaches a server.

Drag the blue box to move it and pull its corner dots to resize it. Detection looks for the non-white bounding box on a white background, so labels with unusual layouts or dark backgrounds may need a manual nudge — that's what the box is for.

Not directly — encrypted PDFs can't be opened in the browser for privacy reasons. Remove the password in your PDF reader first (usually via "Print to PDF"), then upload the unlocked file.