BMP to WebP Converter — Convert BMP to WebP Online
Turn an uncompressed bitmap into a WebP a fraction of its size. Drop your file below and pick WEBP as the output format — free, private, and entirely in your browser with no upload required.
Drop images here or click to browse
Supports HEIC, WEBP, AVIF, BMP, TIFF, SVG, GIF, ICO, PDF, JPG, PNG
100% Private — Your files never leave your device
All conversion happens directly in your browser using JavaScript. Nothing is uploaded to any server. Your images stay on your computer the entire time.
Why Convert BMP to WebP?
Because BMP does not compress. A 24-bit BMP spends three bytes on every pixel and stores them verbatim, so its size is decided by the image's dimensions and nothing else — a blank white frame costs exactly as much as a detailed photograph. WebP compresses those same pixels, and the difference is not incremental.
Taking the 1600 × 2000 photograph from this site's own homepage and running it through the converter above:
- As a 24-bit BMP: 9,600,054 bytes — fixed by the pixel count, whatever the picture shows
- As WebP at the default 92% quality: 245.5 KB, or 97.4% smaller
- As WebP at 50% quality: 54.1 KB, or 99.4% smaller
That is the whole reason this conversion exists. BMP earns its keep when a piece of legacy software demands raw pixels; the moment the file has to cross a network, sit in a web page, or live in cloud storage, those megabytes are pure cost. WebP also brings a genuine alpha channel and animation support, neither of which the plain 24-bit bitmap can express. If you want the file smaller but need every pixel preserved exactly, convert BMP to PNG instead — PNG discards nothing, though the result is still several times larger than the WebP.
BMP vs JPG vs WebP vs AVIF
Every number below is the same source photograph — 1600 × 2000 pixels, 3.2 megapixels — encoded by this converter and measured, not estimated. As a BMP it is 9.2 MB at every setting, because the quality slider has nothing to act on.
| Quality setting | JPG | WebP | AVIF | WebP vs BMP |
|---|---|---|---|---|
| 50% | 108.6 KB | 54.1 KB | 41.5 KB | 99.4% smaller |
| 75% | 219.7 KB | 81.5 KB | 124.2 KB | 99.1% smaller |
| 92% (default) | 310.6 KB | 245.5 KB | 250.9 KB | 97.4% smaller |
WebP beat JPG at every setting on this photo — by 21% at the default and by 63% at 75% quality — so if you were going to make a JPEG, the WebP is smaller. Against AVIF the answer depends on how hard you are compressing: AVIF pulls well ahead at 50% quality, while WebP came out slightly smaller at the top of the range and encodes in a fraction of the time.
The catch is that a “quality” number is not a shared scale. Each codec maps it onto its own quantiser, so the 75% row compares three files that do not look alike. Judge the result with your own eyes, and remember that a different image will land on different numbers. For the two modern codecs head to head, see WebP vs AVIF; for what WebP does to a website's payload, see PNG vs WebP for your website.
How to Convert BMP to WebP
- Drag your BMP file into the drop zone, or click to browse and select it.
- Choose WEBP from the Output Format menu.
- Lower the Quality slider if you want a smaller file, or raise it to stay closer to the original.
- Download the WebP — it's saved straight to your device.
You can drop several bitmaps at once and take them away together as a ZIP. Nothing is uploaded: the conversion runs on your own machine, so even confidential scans and screenshots never leave your computer. WebP encodes quickly — a multi-megapixel bitmap is typically done in well under a second.
When WebP Is the Wrong Choice
WebP wins on size, and size is not always what matters. Reach for something else when:
- You need every pixel preserved. WebP is lossy at the default setting; BMP to PNG is lossless and still cuts the size sharply.
- The image is larger than 16,383 pixels on a side. WebP simply cannot encode it — resize first, or use PNG.
- The file has to open in very old software. BMP to JPG is the universally readable fallback.
- Something downstream demands a bitmap. That is the one job BMP is still good at.
Not sure which format the job calls for? Our image format by use case guide walks through web, print, email, and archive. And if you already have WebP files that a legacy app refuses to open, WebP to BMP handles the return trip.
Frequently Asked Questions
Is WebP better than BMP?
For almost everything except feeding a legacy application raw pixels, yes. BMP applies no compression, so its size is fixed by the pixel count alone — a 1600×2000 photo is always 9,600,054 bytes whether it shows a detailed landscape or a blank white frame. WebP compresses the same pixels to 245.5 KB at this converter's default 92% quality, a 97.4% reduction, and adds transparency, animation, and a lossless mode that BMP has no answer to. BMP wins on exactly one point: every decoder ever written can read it without a library.
How much smaller is WebP than BMP?
Between 97% and 99.4% smaller for a photograph, depending on where you leave the Quality slider. Converting this site's 1600×2000 test photo produced a 245.5 KB WebP at the default 92% quality, 81.5 KB at 75%, and 54.1 KB at 50% — against a fixed 9,600,054-byte BMP. Screenshots and flat graphics compress even further, because WebP finds the repeated colour runs that BMP stores over and over.
Does converting BMP to WebP lose quality?
At the default setting WebP is a lossy format, so it does discard some detail to shrink the file. In practice the loss is very hard to see: the 92% WebP of our test photo measured just over 47 dB PSNR against the original bitmap, comfortably inside the range usually called visually lossless. Because BMP stores uncompressed pixels, this is also the first generation of loss the image has ever suffered, which is the best possible starting point. If you need every pixel preserved exactly, convert BMP to PNG instead — PNG is lossless by definition.
Can I convert BMP to WebP for free?
Yes. This BMP to WebP converter is completely free with no sign-up, watermarks, or file limits. The conversion happens inside your browser, so your bitmaps are never uploaded to a server.
Will a WebP file open everywhere?
In browsers, yes. Chrome, Firefox, Edge, and Opera have supported WebP for years, and Safari added it in version 14 (2020), so every current browser displays WebP. Desktop and design software has caught up more slowly, though modern versions of Windows Photos, macOS Preview, GIMP, and Photoshop all handle it. If a file must open in genuinely ancient software, JPG remains the safest bet.
Is there a size limit on WebP?
Yes, and it is the one place a large bitmap can catch you out: WebP cannot exceed 16,383 pixels in either dimension. BMP has no such ceiling, so a very wide scan or a stitched panorama may need to be cropped or resized before it will encode. Anything within 16,383 × 16,383 converts without complaint.
Does WebP keep the transparency in my BMP?
WebP supports a full alpha channel, but the 24-bit BMPs this converter reads do not carry one, so in practice there is no transparency to preserve. If your source image has transparency and you need to keep it, start from a PNG or WebP rather than a BMP.