Convert BMP to WEBP — modern compression for legacy bitmaps
Drop a BMP below and get a WEBP typically 30 to 100 times smaller than the source, with transparency preserved when present. Runs entirely in your browser.
Your file is processed entirely in your browser. Nothing is uploaded.
BMP files are effectively raw pixel grids with little or no compression, which is why they balloon to sizes other formats would consider absurd: a 4K screenshot can be 32 MB in BMP, compared to under 500 KB in WEBP at high quality. If you have a folder of old BMPs from legacy Windows tools, Paint exports, scanners, or specialized scientific software, converting them to WEBP is the most aggressive size reduction you can get without falling back to JPG. And unlike JPG, WEBP supports transparency, so 32-bit BMPs with an alpha channel can be modernized without losing their transparent backgrounds.
This converter uses the HTML5 Canvas API to decode your BMP in the browser and re-encode it as a WEBP locally. The quality slider controls the compression. At quality 85, the visual difference from the BMP is imperceptible on photographic content, and the file is usually 50 to 100 times smaller. If your BMP is a screenshot or a flat-color illustration, the savings may be slightly less dramatic but still substantial. Your BMP never leaves your device — no upload, no server, no logged copy.
How to convert BMP to WEBP in 4 steps
- 1
Select your BMP
Drop it in the dropzone or click to browse. BMPs of all common color depths are accepted — 1-bit, 8-bit, 24-bit, 32-bit with alpha.
- 2
Choose a quality level
The default of 85 is excellent for most content. Go higher for archival-grade output or lower if storage matters most.
- 3
Wait for the encoding
Canvas reads the raw BMP pixels and encodes them as WEBP. Even huge BMPs finish in a second or two on a modern device.
- 4
Download the tiny WEBP
Save the WEBP and reclaim the disk or bandwidth space. The WEBP is ready for the web or any modern platform.
BMP vs WEBP: the ultimate mismatch
BMP stores pixels as raw bytes with essentially no compression, which made sense on 1990s hardware and makes almost no sense today. WEBP uses a modern frequency-domain and entropy coding pipeline derived from VP8 video, producing files one to two orders of magnitude smaller than BMP at the same perceived quality on most content. BMP has one advantage: everything on a Windows machine can read it without extra software. WEBP has the rest: dramatically smaller files, alpha channel support, universal browser support, and modern pipeline compatibility. On any workflow that does not specifically require BMP output, WEBP wins. The only edge case is extreme simplicity — a BMP viewer exists in every Windows installation since 1990, and nothing else has that track record.
When should you convert BMP to WEBP?
Modernizing a BMP archive
Converting a folder of old BMPs to WEBP can free tens of gigabytes of storage. The conversion is one-time and the originals can be deleted once you verify the output.
Shipping a BMP screenshot to the web
A legacy BMP screenshot is almost always too large for web publishing. WEBP shrinks it to a size that fits Core Web Vitals budgets without any visible quality loss.
Preserving transparency from a 32-bit BMP
If your BMP uses a 32-bit mode with alpha, converting to JPG would destroy the transparency. WEBP preserves the alpha channel and shrinks the file at the same time.
Emailing multiple scanned BMPs in one message
Scanner output in BMP can easily exceed email attachment limits. Converting to WEBP lets you fit dozens of pages in a single message.
Frequently asked questions
- Is WEBP smaller than PNG for BMP input?
- Almost always yes. On photographic content, WEBP at quality 85 is 5 to 10 times smaller than PNG. On flat-color screenshots, lossless WEBP is roughly 25 percent smaller than PNG while being pixel-identical.
- Will the quality be visibly lower?
- At quality 85 or above, the difference from the BMP original is imperceptible on photographic content. On text and sharp edges, you may see very slight artifacts — raise the quality to 95+ or pick PNG if pixel-perfect matters.
- Does WEBP work on Windows?
- Yes. Windows 10 version 1809 (October 2018) and later natively render WEBP in File Explorer, Paint, Photos, and most Windows applications. Older Windows versions may need a viewer plugin or a modern browser to open the file.
- Does the alpha channel carry over from 32-bit BMPs?
- Yes. WEBP supports a full 8-bit alpha channel, identical to PNG’s. If your BMP was saved with alpha, the WEBP output preserves it without loss.
- Is my BMP uploaded?
- No. The conversion is 100 percent client-side through the HTML5 Canvas API. Your BMP is decoded locally, re-encoded locally, and the WEBP is produced locally. FileShrink has no server that touches your files.