BMP3 to SIXEL Converter
FileFlip converts BMP3 to SIXEL entirely inside your browser, using ImageMagick compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a BMP3 file to SIXEL?#
- Drop your BMP3 file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to SIXEL and the conversion starts on its own. FileFlip downloads 14.1 MB of WebAssembly the first time and nothing after that, then runs ImageMagick on your own machine.
- Save the SIXEL file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting BMP3 to SIXEL lose quality?#
No. Converting BMP3 to SIXEL writes the data out again without discarding any of it, so nothing that was in the BMP3 file is lost on the way. What changes is the size of the file, not what is inside it.
Is it safe to convert BMP3 files online?#
Yes, because nothing is uploaded. FileFlip converts BMP3 files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What BMP3 to SIXEL actually does to the file#
Converting BMP3 to SIXEL runs on ImageMagick, downloads 14.1 MB of WebAssembly the first time and nothing after that, writes the data out again without discarding any of it.
| Engine | ImageMagick |
|---|---|
| Conversion path | One step: BMP3 → SIXEL |
| Downloaded to your browser | 14.1 MB, once, then cached by your browser |
| Quality | Lossless |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
Worth knowing before you start:
- the target holds at most 256 colours, so a full-colour image is quantised to a palette
What is a BMP3 file?#
BMP3 is ImageMagick's name for a Windows bitmap saved with the 40-byte BITMAPINFOHEADER that Windows 3.0 introduced in 1990, an encoding choice rather than a different file format, and it's the header structure the overwhelming majority of ordinary .bmp files already use.
Choose BMP3 for maximum compatibility, since it's the header format nearly all BMP-reading software expects.
Convert away from BMP to PNG when the image needs transparency, or when you want lossless compression smaller than BMP3's largely uncompressed pixel data.
What is a SIXEL file?#
A SIXEL file holds a bitmap encoded entirely as printable ASCII characters, using DEC's six-pixel-tall encoding scheme, so it can be sent to a printer or terminal over a plain 7-bit serial link and displayed without any separate image protocol.
Use Sixel when an image needs to display inline inside a terminal session, such as showing a chart or a thumbnail over SSH without opening a separate viewer.
Convert a Sixel image to PNG once it needs to be viewed anywhere outside a terminal emulator that understands the encoding.
BMP3 to SIXEL questions people ask#
What is BMP3?
BMP3 is ImageMagick's name for a standard Windows bitmap written with the 40-byte BITMAPINFOHEADER, not a separate format. It's the same header structure that almost every ordinary .bmp file already uses.
Is BMP3 the same as a normal BMP file?
Yes, in practice. Windows has used the BITMAPINFOHEADER as its default bitmap header since Windows 3.0 in 1990, so a plain .bmp saved by most modern software is already what ImageMagick calls BMP3.
Does BMP3 support transparency?
No. The BITMAPINFOHEADER that BMP3 writes has no alpha channel; that was added in later Windows header versions. A BMP3 file is always fully opaque.
What is a SIXEL file?
A SIXEL file is a bitmap image encoded as printable ASCII text using DEC's six-pixel-tall scheme, originally built in the early 1980s so DEC printers and terminals could receive graphics over the same serial link used for plain text.