A BMP heading for a website
The largest saving of any option here, with transparency preserved. Resize to the display width first and the two reductions compound.
BMP to WebP
Convert BMP to WebP in your browser for the smallest file of the three options, with transparency preserved.
Maintained by Roshan.
Browser-local tool
Use BMP to WebP
Your image is decoded and re-encoded on this device. No upload request is made.
WebP preserves transparent pixels. Maximum quality minimizes further loss, but browser encoders do not guarantee mathematically lossless WebP.
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Browse all image toolsAbout BMP to WebP
If the destination is a web page, WebP is the best of the three targets available for a BMP. It compresses more efficiently than JPEG at the same visible quality, and unlike JPEG it keeps an alpha channel, so a 32-bit BMP with transparency survives the trip. Given that BMP is the least efficient common image format and WebP is among the most efficient, the size difference between input and output tends to be the largest of any conversion on this site - reductions of ninety-five per cent or more are ordinary rather than exceptional. The caveat is reach rather than quality: WebP is decoded by every current browser but is not a universal interchange format, so it is the right answer for a website and the wrong one for a file being handed to someone whose software you do not know.
Shape and export choices
- The BMP is decoded to pixels with any alpha channel intact.
- A transparency-enabled canvas is created at the source dimensions and the image drawn without a background being imposed.
- The pixels are re-encoded as lossy WebP at a high quality setting, which is where the very large size reduction comes from.
- Transparency is carried into the WebP alpha channel, so cut-out images do not gain a white box.
- Both byte counts are shown, since the difference here is usually striking enough to be worth seeing.
Good fits for BMP to WebP
A batch of BMPs eating disk space
WebP gives the smallest result. Keep the originals if they are masters, since this step is lossy.
Check the image before download
- The encoding is lossy. For a first compression of an uncompressed source the difference is generally invisible on photographs, but it is real.
- Text and sharp diagrams soften slightly under any lossy encoder. Choose PNG when the image is a screenshot.
- Some desktop software and email clients still refuse WebP, so it is a poor choice for a file being sent to someone else.
- Unusual or RLE-compressed BMP variants may not decode in a browser.
- Metadata in the BMP header, including any recorded print resolution, is not carried over.
Questions about BMP to WebP
Which target gives the smallest file?
WebP, usually by a clear margin over JPEG and by an enormous margin over the original BMP.
Is transparency kept?
Yes. WebP has a real alpha channel, unlike JPEG.
Is anything lost?
Yes, this is lossy compression. It is rarely visible on photographs and can be on text or diagrams.
Should I send WebP to a colleague?
Probably not. Use PNG or JPG when you do not control what will open the file.
Related tools
BMP to PNG
Convert BMP to PNG in your browser. Lossless, so nothing is degraded, and typically a fraction of the original size.
BMP to JPG
Convert a BMP to JPG in your browser. BMP files are uncompressed, so the saving is usually enormous.
JPG to WebP
Re-encode a JPG photo as WebP in your browser to cut page weight. Compare the before and after byte counts before you download.