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BMP to WebP Converter

BMP is uncompressed — files are enormous for no visual benefit. Converting to WebP gives you files roughly 25–35% smaller than JPG at the same visual quality — ideal for websites. The size is the entire issue — email attachment limits, upload caps and disk space all bite long before quality does. Common BMP variants also carry no alpha channel, so there is no transparency to lose, and none to gain by staying put. Images going onto a website, where the 25–35% saving over JPEG is bandwidth and Core Web Vitals rather than an abstraction. Drop your files below; everything runs locally through the Canvas API, with no upload, no size limit and no account. Check where the result has to open before you commit to a batch — every current browser reads WebP, but desktop and office software is patchier, so it is a format to publish in rather than to hand to somebody.

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or click to browse — JPG, PNG, WebP, HEIC, AVIF, GIF, BMP, SVG

Private: files never leave your device

What a BMP file actually is

BMP is Microsoft's original raster format and in normal use stores pixels with no compression at all: three bytes per pixel, plus a header. A 12-megapixel photo lands around 36 MB. An optional run-length mode exists but is rarely produced.

BMPs turn up from legacy Windows software, older scanner drivers, industrial and medical equipment, and Paint on an ancient machine. New files in this format are almost always a sign that something in the chain has not been updated in a long time.

What you get from WebP

WebP output uses lossy compression with a quality control, but unlike JPEG it can keep an alpha channel at the same time — one format for photographs and for graphics with transparency.

Every current browser reads WebP; Safari joined in version 14 in 2020, which was the last real holdout. Desktop applications are patchier, so it is a format to publish in rather than to archive in.

What changes when you convert BMP to WebP

This is where the file size actually drops. A BMP stores its image without discarding anything, and WebP's lossy mode decides what the eye will not miss — typically landing 25–35% below a JPEG of matching quality, and keeping the alpha channel while it does so, which JPEG cannot. The catch is not visual but practical: WebP is a format to publish in, and a poor choice for anything you are handing to someone else's desktop software.

There is no transparency to preserve — BMP files do not carry an alpha channel, so every pixel is opaque to begin with. Converting to a format that supports transparency does not create any; it only means you could add it later in an editor.

Expect the file size to collapse. BMP stores three bytes per pixel with no compression at all, so a 12-megapixel image sits around 36 MB before anything is done to it. Re-encoding as WebP routinely produces a file a fiftieth of that size with nothing visible lost, because there was never any compression to preserve.

Frequently asked questions

Is this BMP to WebP converter really free and private?

Yes. Conversion happens entirely in your browser using the Canvas API — your BMP bitmaps are never uploaded to a server, there is no file limit, no watermark and no sign-up.

Can I convert multiple BMP files at once?

Yes — drop any number of files and they convert in one batch. Use "Download all" to save the results as a single ZIP.

Does converting BMP to WebP lose quality?

This is where the file size actually drops. A BMP stores its image without discarding anything, and WebP's lossy mode decides what the eye will not miss — typically landing 25–35% below a JPEG of matching quality, and keeping the alpha channel while it does so, which JPEG cannot. The catch is not visual but practical: WebP is a format to publish in, and a poor choice for anything you are handing to someone else's desktop software.

Will a WebP file open on every device?

In a browser, yes — every current browser has supported WebP since Safari 14 in 2020. Outside the browser it is less certain: older desktop editors, some print workflows and a number of CMS uploaders still reject it. Use WebP for the web and JPG or PNG for anything you are handing to someone else.

Will I lose anything by leaving BMP behind?

Effectively nothing. BMP stores raw pixels with no compression and, in its common variants, no transparency — so there is no quality advantage to preserve. The conversion is close to pure size saving.

Related conversions

JPG → WebPPNG → WebPHEIC → WebPAVIF → WebPGIF → WebPBMP → JPG

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