Processed entirely on your device — nothing is uploaded
How to use the bmp to webp converter
- 1Drop your BMP files onto the box above, or click to browse for them.
- 2Adjust the quality slider if you want a smaller file or a sharper result.
- 3Press Convert and wait while your browser re-encodes each image.
- 4Download the finished WebP files.
Why convert BMP to WebP?
An uncompressed Windows-native format that stores raw pixel data with essentially no compression at all. That is exactly what you want when the file is being archived or edited, and an obstacle when it has to be emailed, uploaded or served on a web page. WebP solves the second problem.
Google's web-first format that offers both lossy and lossless modes plus transparency in a single container. For a BMP source specifically, the payoff is typically 25-35% smaller than JPEG at visually equivalent quality — and alongside that, supports transparency and animation, which JPEG cannot do at all and supported by every browser released since 2020, making it safe for production websites.
The cost of the switch is worth stating plainly before you make it: some desktop software, older printers and a few social platforms still refuse WebP uploads and lossy WebP is still lossy — re-encoding an already-compressed image compounds the damage. Weigh that against what BMP was giving you, which was trivially simple structure that old industrial and medical software can always read.
Where BMP files usually come from
Most people arrive at this page holding one of three things: output from scanner software or an industrial machine-vision camera, screenshots taken by a legacy Windows application, or frames dumped by scientific or medical imaging equipment.
Knowing which one you have matters, because it changes the right settings. Photographic content tolerates aggressive compression well — the eye is forgiving about noise in a sky or a skin tone. Screenshots, charts and line art do not: they contain hard edges and small text, which is precisely what lossy compression handles worst. If your BMP is the second kind, push the quality slider higher than feels necessary.
BMP originated in legacy Windows software, scanners and industrial equipment, and that lineage explains most of its behaviour: an uncompressed Windows-native format that stores raw pixel data with essentially no compression at all.
What happens to quality when you convert BMP to WebP
BMP stores every pixel exactly as it was authored, while WebP discards detail your eye is unlikely to notice in order to shrink the file. This conversion is therefore the first lossy step in your image's life, and it is not reversible. At quality 90 the difference is invisible on a photograph; on a BMP screenshot full of small text you will start to see faint halos around the letters below about 85.
Keep the original BMP somewhere safe. You can always produce another WebP from it, but you can never recover the BMP from the WebP.
How much smaller (or larger) will the file be?
Expect a dramatic reduction. BMP stores raw pixels with no compression at all, so a 12-megapixel image occupies roughly 36 MB. The same picture as WebP typically lands between 1 and 4 MB — a reduction of 90% or more. This is the conversion with the largest size payoff of any on this site.
The quality slider is your main control. Dropping from 92 to 80 typically halves the file for a difference most people cannot see at normal viewing distance. Below 70, artefacts become obvious on skin tones, skies and any smooth gradient. If you are unsure, convert once at 85 and look at the result before going lower.
When converting BMP to WebP is the wrong move
This conversion is not always the right answer, and it is cheaper to know that now than after you have replaced your originals. Skip it if this is a master file you intend to edit again later, because every future save compounds the loss and the destination is a printer, a government upload portal or older desktop software, several of which still reject WebP outright.
A reasonable default: keep your BMP originals in a folder you do not touch, and treat the WebP output as a derived, disposable copy for whatever you are publishing or sending. That way a bad quality setting costs you a re-export rather than the image.
Your BMP files never leave your device
Server-side conversion is the industry default, which means the normal price of a free converter is a copy of your image living somewhere you cannot see.
This converter does not work that way. Your BMP is decoded by the browser's own image pipeline, drawn into an off-screen canvas, and re-encoded as WebP — all inside this tab, on your processor. There is no upload progress bar because there is no upload, no queue because there is no server, and nothing to delete afterwards.
Nothing here is taken on trust — disconnect from the network after the page loads and the tool still converts, which it could not do if a server were involved. A practical side effect is that speed depends on your own hardware rather than on someone else's server load, and there is no file size cap beyond your available memory.
Frequently asked questions
Is this BMP to WebP converter really free?
Yes — no account, no watermark, no daily cap. The conversion runs on your own processor, so it costs nothing to serve and there is nothing to meter.
Are my BMP files uploaded anywhere?
No. The file is read locally, decoded into a canvas and re-encoded to WebP entirely within this browser tab. No image data crosses the network at any point.
Can I convert several BMP files at once?
Yes. Drop in as many as you like and each is converted with the same settings, one at a time so a large batch does not exhaust your memory.
Will WebP work everywhere?
Every browser released since 2020 displays WebP, so it is safe for websites. Some desktop applications, older printers and a few upload forms still reject it — use JPG or PNG if you hit one.
Why is my BMP so much bigger than everything else?
BMP stores raw pixel data with essentially no compression, so size scales directly with resolution. A 12-megapixel BMP is around 36 MB regardless of what the picture shows.
Does the converter change my image dimensions?
Not unless you ask. Output keeps the exact pixel dimensions of the source; the max-width box is empty by default and only resizes when you fill it in.