Convert BMP to PNG
Turn your BMP into a PNG. BMP stores a picture as plain rows of pixels with nothing squeezed out, which makes it easy for old Windows software and simple devices to read. Your file never leaves your computer.
Need the other direction? Convert PNG to BMP
How to convert BMP to PNG
- 1 Drop your BMP .bmp or .dib file onto the page, or click to browse for it.
- 2 Check the options. Nothing is thrown away on the way to PNG, so there is no quality dial to set.
- 3 Convert. The work happens on your own machine, so how long it takes depends on your computer and the file.
- 4 Download the PNG, or add more files and do the whole set in one go.
Why convert BMP to PNG
- Nothing is ever thrown away, so re-saving never degrades the picture.
- Smooth, partial transparency rather than hard on-or-off edges.
- Logos and icons that need a transparent background.
- BMP: essentially unusable on the web because of that size.
BMP compared with PNG
How the two formats differ on the things that decide whether a conversion is worth making.
| Property | BMP | PNG |
|---|---|---|
| File extension | .bmp | .png |
| Compression | Uncompressed | Lossless |
| Colour depth | 1, 4, 8, 16, 24 or 32 bits per pixel | Up to 16 bits per channel, 48-bit colour |
| Typical file size | Largest | Larger |
| Browser support | All current browsers | Every browser |
| Introduced | 1986 | 1996 |
| Developed by | Microsoft | PNG Development Group / W3C |
| Standard | Proprietary | Open |
Quality and what changes
Both sides are lossless, so every pixel survives the trip intact and converting back returns the same image. What changes is the size and what the file can carry: PNG compresses the same data with a different algorithm, so the size can move in either direction.
- One PNG limitation to keep in mind: encoding at maximum compression is slow on large images.
Questions about BMP to PNG
Is my BMP file uploaded anywhere?
No. The whole thing runs inside the browser tab you already have open. Your BMP is read straight from your own disk, converted on your machine and handed back as a PNG. Nothing is sent anywhere, nothing is stored and there is no account.
Is there a file size limit?
There is no server-side limit because no server sees the file. The real ceiling is your device memory, since the input and the output both have to fit in the tab. A few hundred megabytes is usually fine on a desktop machine and considerably less on a phone.
Can I convert several BMP files at once?
Yes. Add as many as you like and they are processed one after another, then offered as separate PNG downloads or as a single ZIP. Speed depends on your own processor rather than on a queue.
Does the converter work offline?
Yes, after the page has loaded once. The engine is cached by the browser, so you can disconnect, reload and keep converting. That falls out of doing the work locally rather than being a separate mode you switch on.