Why Your Scan Was Rejected
If a website refuses your scanned document with messages like “File too large”, “Upload limit exceeded”, or “Attachment rejected”, the problem is often the file format — not the scanner. Many older scanners and Windows systems still output BMP files. BMP stores raw, uncompressed pixel data, so even a single black-and-white page can exceed 20–30MB. Banks, government portals, school systems, and email providers commonly enforce strict limits between 5MB and 10MB, causing these scans to fail instantly.
This tool fixes the blockage by converting the rejected BMP scan into a standard PDF while dramatically reducing file size — usually by 80–95% — so the document passes upload checks without re-scanning.
How This Fix Works
The BMP image is decoded in your browser and re-encoded inside a PDF container using JPEG compression tuned for document scans. Text, signatures, and stamps remain clear, while redundant pixel data that BMP preserves unnecessarily is discarded. The resulting PDF conforms to the formats expected by upload validators used by financial institutions and public agencies.
Local Processing for Sensitive Scans
Scanned BMP files often contain passports, ID cards, contracts, or signed forms. Uploading raw scans to third-party servers introduces avoidable risk. This converter runs entirely client-side using the browser’s Canvas API. The file is processed in browser memory only; there is no network transmission, no background upload, and no server storage. You can verify this by disconnecting from the internet or using airplane mode — the conversion still completes.
Technical Note: Why Compression Is Safe Here
BMP preserves every pixel exactly, which is unnecessary for scanned documents. During conversion, visual data is encoded using perceptual JPEG compression at a calibrated quality level designed for text and line art. This removes imperceptible detail while keeping characters readable and edges intact. For standard administrative uploads and typical printing needs, the output PDF meets visual and compliance expectations while remaining a fraction of the original size.