Dramatically smaller files
BMP stores every pixel uncompressed, so it is enormous for its dimensions. WebP applies modern compression and typically cuts the weight by well over ninety percent.
ImageRuns in your browser
BMP to WebP Converter
Shrink a bulky uncompressed BMP into a lean, web-ready WebP without losing detail — no upload.
- Upload
- Batch upload supported · 25 MB max
- Privacy
- Nothing is uploaded
- Cost
- Free · no sign-up · no watermark
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Processed entirely on your device
Your file is read, transformed and re-encoded inside this browser tab using JavaScript. There is no upload endpoint — nothing leaves your machine, nothing is stored, and the result is created as a local object URL that disappears when you close the page.
Overview
About the BMP to WebP Converter
Convert BMP to WebP free online — re-encode a large uncompressed bitmap into a compact WebP with a quality slider and transparency support. Batch, no upload.
Why convert a BMP to WebP
The Windows bitmap format stores raw, uncompressed pixels. That was convenient for early desktop software but makes BMP files enormous and impractical for the web. Converting a BMP to WebP replaces that bulk with a modern codec designed for fast pages, usually shrinking the file by more than ninety percent with no visible change.
Choosing quality and keeping transparency
Because the source is lossless, the quality slider is the only thing deciding how much detail survives. Values of 90% and above keep a re-encoded WebP effectively identical to the original bitmap, while lower values trade a little fidelity for even smaller files. If the BMP carried an alpha channel, WebP preserves it, so transparent artwork stays cleanly cut out rather than landing on a solid background.
Batch conversion, privately
Up to twenty files convert in one run, each up to 25 MB, processed one at a time so memory stays predictable, with a summary of size before and after. Each result is named after its source with a .webp extension. Nothing is uploaded: the decode, the re-encode and every download happen inside the tab, with no account and no watermark, because there is no server on the other end.
Step by step
How to use the BMP to WebP Converter
Drop one or more images onto the upload area — a .bmp or any other format, detected automatically.
Set the quality slider; 85-95% preserves fine detail from an uncompressed source.
Keep transparency if the BMP carried an alpha channel — WebP retains it, JPG would not.
Press Convert to WebP — each bitmap is decoded and re-encoded locally, one file at a time.
Read the size change in the result row, then download each WebP or the whole batch.
Why use it
Benefits and common use cases
What this tool is good for, and what it deliberately does not try to do.
Ready for the web
Browsers, CDNs and page-speed budgets all favour WebP. Converting a desktop bitmap to WebP makes it practical to publish without a heavy download.
Detail you can trust
Because the source is lossless, you choose how much to compress. A high quality setting keeps the re-encoded WebP visually identical to the original bitmap.
Private by construction
The decode and re-encode run inside the browser's image pipeline, so nothing is uploaded and no copy of your bitmap is stored anywhere.
Questions
Frequently asked questions
Short, honest answers about quality, limits and privacy.
Why is my BMP so large?
BMP is an uncompressed Windows bitmap: it stores raw pixel data with little or no compression. That makes files big and slow to publish, which is exactly why converting to WebP helps.
Is BMP to WebP lossy?
WebP can be lossy or lossless; this tool uses the lossy mode at the quality you set. From an already-large BMP, a quality of 90% or above is visually indistinguishable while being far smaller.
Does WebP keep transparency?
Yes. If the bitmap carried an alpha channel, WebP preserves it, so cut-out artwork stays transparent — an advantage over converting the same BMP to JPG.
Are my files uploaded to a server?
Never. There is no upload endpoint — decoding, re-encoding and every download happen inside your tab, using local object URLs released shortly after the click.