Convert BMP to WebP Online
Upload a Windows bitmap and get a WebP file at the same pixel dimensions, encoded on our servers. The WebP side is lossy and there is no quality or lossless setting on this page, so if you need every pixel kept exactly, convert the BMP to PNG instead.
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Why convert BMP to WebP
BMP stores pixels almost raw: a 4000 x 3000 24-bit bitmap is around 35 MB on disk, because there is no real compression to speak of. That is fine for a scanner dump, a screenshot from an older Windows tool, or a game asset pipeline, but it is the wrong thing to put on a web page. WebP was designed for that job and is read by every current browser, which is why people arrive here with a folder of .bmp files and a site that needs to load.
On this page the bitmap is decoded by ImageMagick, which handles the common BMP v3 to v5 layouts, and the result is written out with the WebP encoder's default lossy settings. Everything happens in worker processes on our servers after the upload; nothing is converted inside your browser, and there are no resolution, DPI or compression controls to set.
Pixel dimensions come through unchanged: nothing is resized, cropped or padded. What you give up is exactness. WebP here is a lossy encode, so flat-color graphics, thin lines and small text can pick up soft edges that were crisp in the bitmap. Transparency is the other open question. Plain 24-bit BMP files have no alpha channel at all, and for a 32-bit BMP v5 with alpha we do not promise the channel survives this path, so if cut-out edges matter, run the file through BMP to PNG, which keeps alpha intact and is lossless.
The people who need this pair are usually dealing with legacy output: Paint and other Windows utilities still save BMP, some scanners and lab instruments only write BMP, and plenty of older applications export it by default. If the destination is a website, a theme, an app asset folder or a CMS that rejects .bmp uploads, WebP is the smaller file to ship.
How to convert BMP to WebP
- Check the size of the bitmap first. Because BMP is uncompressed, large images hit the upload cap quickly: 50 MB per file without an account, 100 MB with a free one. If your file is over the cap, downscale or re-export it in your image editor before uploading.
- Drop the BMP onto this page. You can send several at once in one request, up to 10 files as a guest or free user, 25 on Plus and 50 on Pro.
- Start the conversion. The upload is decoded and re-encoded as WebP on our servers, and each file comes back with its own download link.
- Download the results. Links stay valid for about four hours, after which the output is deleted automatically.
- Open the WebP at 100% zoom and look at text, logos and hard edges. If lossy artifacts bother you on flat graphics, use the BMP to PNG converter for those particular files and keep WebP for photographic ones.
What this converter does
- Decodes BMP v3 through v5 with ImageMagick, so you do not need Photoshop or a plugin to read the bitmap
- Keeps the original pixel width and height: no automatic resizing, cropping or upscaling
- Converts up to a full batch in one request, within the per-plan limits of 10 files for guests and free accounts, 25 on Plus and 50 on Pro
- Works from any browser and operating system, because the decoding and encoding run on our servers, not on your machine
- Gives each converted file its own download link, valid for roughly four hours; the uploaded bitmap is deleted as soon as the job finishes
- Sits next to the lossless BMP to PNG path for images where exact pixels or an alpha channel matter more than file size
Video Tutorial
Watch this step-by-step tutorial to learn how to convert BMP files to WEBP format online for free using MiConvert.com. No software installation required.
BMP to WebP questions
Can I pick the WebP quality, or ask for lossless WebP?
No. This page has no quality slider and no lossless toggle; the encoder's default lossy settings are used. If you need pixel-for-pixel fidelity, convert the BMP to PNG, which is lossless, and compress it on the web server instead.
Will the transparency in my 32-bit BMP be preserved?
We do not guarantee it on this path. Most BMP files are 24-bit and have no alpha channel at all; for 32-bit BMP v5 files with alpha, convert to PNG if the cut-out edges have to survive, since the PNG path keeps the alpha channel.
Why did my very large BMP fail to convert?
Two separate caps can stop it. The upload limit is 50 MB for guests and 100 MB with a free account, and the image decoder itself refuses images wider or taller than 16,000 pixels or over 128 megapixels, reporting "width or height exceeds limit" or "cache resources exhausted". Downscale the bitmap in an editor and convert the smaller version.
Will every program open the WebP file afterward?
Current versions of Chrome, Edge, Firefox and Safari display WebP, and so do most modern image viewers and design tools. Some older desktop software, print workflows and email clients still do not read .webp, so keep a PNG or JPG copy if you have to hand the image to one of those.
Can I convert a bitmap to vector here?
Not from BMP. Our tracing tool accepts JPG and PNG sources and produces a single-color silhouette with potrace, not full-color editable vector artwork. For a real vector redraw of a logo you need to trace it manually in Illustrator or Inkscape.
The site says my file is actually a video, or a macOS resource fork. What happened?
Content is sniffed, not trusted by extension. An MP4, MOV or MKV renamed to .bmp is rejected and belongs in the video converter, and the small AppleDouble files macOS creates with a leading "._" are rejected too. Upload the real bitmap, not the companion file.
What happens to my files after the conversion?
The uploaded BMP is deleted as soon as the job's last attempt ends. The converted WebP stays on our download server for about four hours behind a random, unguessable link, then it is removed. File names, sizes and outcomes are recorded in our logs, and if you are signed in, the conversion also appears in your account history, so this is not an anonymous drop box.
Is there a way to convert BMP to WebP without uploading anything?
Not with this tool: the conversion runs on our servers, so the file is transferred over HTTPS and processed there. For an offline workflow, ImageMagick's command line or GIMP's export dialog will do the same job on your own machine.