BMP to WebP converter
Convert BMP images to WebP in your browser.
Processed in your browser. This file is converted on your device and is never uploaded.
Converter
.bmp, .dib up to 50 MB. You can also drag a file here.
No file selected.
About this tool
BMP turns up in output from older Windows software, scanners, and some scientific instruments. WebP is typically 25 to 35 percent smaller than JPEG at the same visible quality, and unlike JPEG it keeps transparency.
This tool converts BMP to WebP entirely in your browser. The image is decoded, drawn, and re-encoded on your device, so nothing is uploaded and the size of the file costs you no waiting.
Supported formats and limits
- Input
- .bmp, .dib
- Output
- .webp (image/webp)
- Output name
- The original name with the new extension, for example photo.bmp becomes photo.webp.
- File size limit
- 50 MB
- Processing
- In your browser. The file is not uploaded.
BMP against WebP
| Feature | BMP | WebP |
|---|---|---|
| Compression | None, stored as written | Lossless or lossy |
| Colour | 8 bits per channel | 8 bits per channel |
| Transparency | None | Full alpha channel |
| Animation | No | Yes |
| Keeps EXIF | No | Yes |
| Browser support | Every browser since 1995 | Chrome 32, Firefox 65, Safari 14 |
| Size of a photograph | 8 to 20 times a JPG | 25 to 35 percent smaller than a JPG |
| Published | 1990 | 2010 |
When you would want this
You need the background to stay transparent
WebP carries a full alpha channel and BMP does not carry a usable one, so this is the conversion that lets a logo or a cut-out sit on any background without a white box around it. Anything you are going to place over a coloured surface, a photograph, or a gradient wants to be in a format that can say a pixel is only partly there.
The file has to be smaller
A photograph as WebP is roughly 0.65 to 0.75 times the size of the same picture as JPG, against 8 to 20 for BMP. On a page that matters twice: less to download, and a faster largest-contentful-paint, which is one of the things a search engine measures. For an email attachment or an upload limit it just matters once.
How to use it
- Choose a .bmp / .dib file, or drag one onto the page.
- Pick a quality level.
- Optionally set a width or height to resize at the same time.
- Select Convert, then download the WebP file.
Limitations
- The output is lossy WebP, so it is not a byte-exact copy of the original.
- A few older programs, email clients, and design tools still cannot open WebP.
- Metadata is not preserved. EXIF fields, including camera settings and GPS location, are dropped, which is a privacy benefit but worth knowing if you rely on them.
- Colour profiles are not preserved, so an image in a wide-gamut profile may shift slightly.
- The camera's EXIF orientation is applied, so a photo taken sideways comes out upright rather than rotated.
Common problems
The WebP will not open in an older program
WebP arrived long after BMP, and software written before it existed has no way to read it. Browsers gained support at Chrome 32, Firefox 65, Safari 14, and anything predating those versions sees a file it does not recognise.
Convert to PNG instead when the file has to open anywhere at all. Keep WebP for the web, where you know what is reading it.
Other ways to do this
The program already on your computer
GIMP, Photoshop 23 and later, recent versions of Preview will open a BMP and save it as WebP, and if you have one of them installed and only one file to convert, that is a perfectly good answer. It stays on your machine the same way this does. Where it stops being convenient is a folder of forty files, or a machine you do not own.
ImageMagick, from a terminal
One command converts a directory: magick mogrify -format WebP *.BMP. If you already have it installed this is the fastest way to do a hundred files, and it scripts. It is also a dependency to install and a syntax to learn, which is a poor trade for converting one image once.
An online converter that uploads
Most sites offering this send your file to a server, convert it there, and give you a link back. They can do formats a browser cannot, which is a real advantage. The cost is that your file was on somebody else's machine, governed by a retention policy you did not read. That is the whole difference here: this page converts BMP to WebP using code your browser already downloaded, so there is no server holding it afterwards.
Frequently asked questions
- Is my image uploaded?
- No. The conversion runs entirely in your browser. The image never leaves your device and no request carrying it is made.
- Which quality should I choose?
- 85% is a good default for photographs and is usually indistinguishable from the original at normal viewing size. Lower settings become visible on sharp edges and in smooth gradients such as skies.
- Will the WebP be bigger or smaller than the BMP?
- Smaller or larger depending on the pair, and here the arithmetic is public: a photograph as BMP runs 8 to 20 times the size of the same picture as JPG, and as WebP it runs 0.65 to 0.75. The comparison table above states both, so you can tell before converting rather than after.
- Will the WebP open everywhere?
- Not everywhere, and it is worth knowing before you send one. Browsers read WebP from the versions listed in the table above, and software older than that has no way to open it. For anything going to a person or a system whose tools you do not control, PNG or JPG remains the safe answer.
- Why is my BMP file so enormous?
- Because BMP barely compresses: it stores each pixel more or less as written, so the size is width times height times bytes per pixel and almost nothing else. That is why it opens instantly and why it is impractical to send. Converting to WebP is the usual fix, and the size drops by a large multiple.
- Can I resize while converting?
- Yes. Set a width, a height, or both. With proportions kept, one dimension is derived from the other, and giving both fits the image inside that box rather than distorting it.
- Do I need to install anything or create an account to use BMP to WebP converter?
- No, to all of it. BMP to WebP converter runs inside the browser you already have, with no sign-up, no download, no watermark on the result, and no cap on how many files you convert. There is nothing to uninstall afterwards either, because nothing was installed.
- Does BMP to WebP converter work offline?
- Once the page has loaded, yes. The conversion runs on your device, so it needs no connection to do the work. The first visit fetches the page and the code that does the converting; after that a lost connection stops nothing, and a converted file appears exactly as it would online.
- How large a file can BMP to WebP converter handle?
- The limit is 50 MB. It is a deliberate one rather than a technical ceiling: the real constraint is memory, and a file that decodes to more than the device can hold fails in a way that is hard to explain. Phones run out well before laptops do, which is why the limit is set where it is.
- Can I convert several files at once with BMP to WebP converter?
- Not here: this tool takes one file at a time, because what it does depends on choices you make about that particular file. Convert them one after another, or look at the batch converters in the same category, which are built for a folder at a time.