Convert BMP to WebP

Output is typically about 94% smaller.

Files stay on your device
No upload, no waiting
No sign-up, no watermark

or drag files here · processed on your device

Quality: 82

80 is visually lossless for most photos. Below 70, artefacts show in gradients.

How it works

Add your BMP file
Drag a BMP file onto the drop zone, or click to browse. You can select several at once.
Choose your settings
Adjust the quality slider if you want a smaller file or a sharper result. 80 suits most photographs.
Download the WebP
Conversion runs on your device as soon as each file is added — no upload, no queue. Download each result when it is ready.

All image tools

Questions

Can I convert a whole folder of BMP files at once?

Yes — add them all and each is processed in turn on your device. They are handled sequentially rather than in parallel so that a large batch cannot lock up a phone or a laptop; expect it to work steadily through the queue rather than finishing everything at once.

Will converting BMP to WebP make the file smaller?

Usually, yes. A 12-megapixel photo is around 36 MB as BMP and around 2.1 MB as WebP — about 94% smaller. Because WebP is lossless the result depends entirely on the image content — flat colour and text compress far better than photographic detail.

Does converting BMP to WebP lose quality?

A little, by design. BMP is lossless and WebP is lossy, so some detail is discarded in exchange for a much smaller file. At quality 80–90 the result is visually indistinguishable from the original for photographs. For screenshots, logos or anything with sharp text, stay with a lossless format instead — lossy compression creates visible halos around hard edges.

Is transparency preserved when converting BMP to WebP?

Yes. Both BMP and WebP support an alpha channel, so transparent and semi-transparent pixels carry across unchanged — a logo with a cut-out background stays cut out, and soft drop shadows keep their gradient rather than picking up a white halo. Because WebP can compress lossily, a very hard edge against transparency may pick up slight softness at high compression; keep quality at 85 or above for cut-out graphics.

Why are BMP files so large?

BMP stores pixels essentially uncompressed — three or four bytes per pixel with no encoding at all. A 12-megapixel photo therefore lands around 36 MB, roughly 11× the same image as a JPEG. That simplicity is deliberate: legacy Windows software and embedded devices can read BMP with almost no code.

About bmp to webp

Why people convert BMP to WebP

Putting legacy assets on the web — usually a batch of old bitmaps that need to become page-ready without a manual pass through an editor.

The biggest size win of the three targets, and it keeps transparency where the BMP variant had it. Sensible for a bulk migration of old artwork.

Worth knowing: Check that the BMP is not an 8-bit palettised variant that already lost colour before you got to it. WebP will faithfully preserve a limited palette rather than restoring what was thrown away.

BMP and WebP side by side

	BMP	WebP
Full name	Bitmap Image File	WebP
Compression	Lossless	Lossy or lossless
Transparency	Yes — alpha channel	Yes — alpha channel
Animation	No	Yes, in the format
Browser support	Supported in all major browsers, though rarely used on the web	All modern browsers — Chrome 32+, Firefox 65+, Safari 14+ (2020), Edge 18+
Typical 12 MP photo	~36 MB	~2.1 MB
Usually used for	Legacy Windows applications, scanners and embedded displays	Web images where page weight matters and modern browsers are the audience

On a typical 12-megapixel phone photo, the WebP output comes out about 94% smaller than the BMP original. These are order-of-magnitude figures for one kind of image — your own results will vary a great deal, because flat colour, text and line art behave nothing like photographic detail, and the quality slider moves the figure substantially.

What to watch out for

Not accepted by some older desktop software and print workflows
Slightly slower to encode than JPEG
Larger than AVIF at the same quality

About the two formats

BMP stores pixels essentially uncompressed, which makes it enormous — a 12-megapixel photo lands around 36 MB, roughly 11× the same image as a JPEG. It persists mainly inside legacy Windows software, scanning utilities and embedded systems where decoding simplicity beats file size.

WebP is the pragmatic modern choice for the web: roughly 25–35% smaller than JPEG at comparable quality, with transparency and animation that JPEG lacks, and — since Safari 14 in 2020 — support in every browser that matters. It is the format to reach for when you want smaller pages without worrying about fallbacks.

Other conversions

Everything runs on your device — nothing is uploaded, so there is no size limit, no queue and no copy left on a server afterwards. There is more on how browser-based conversion works if you want the detail. Otherwise, browse every image tool, or convert WebP back to BMP.