What Is a BMP or DIB File?

A file with the BMP file extension is a Device-Independent Bitmap Graphic file, and may therefore be called a DIB file for short. They're also known as bitmap image files or just bitmaps.

BMP files can store both monochrome and color image data in various color/bit depths. Although most BMPs are uncompressed and so are fairly large in size, they can optionally become smaller through lossless data compression.

The BMP format is very common, so common in fact that many seemingly proprietary image formats are actually just renamed BMP files!

XBM and its newer XPM format are two image formats that are similar to DIB/BMP.

Note: DIB and BMP files aren't truly identical because the two have different header information. See Microsoft's DIBs and Their Use for more information on this format.

The Device-Independent Bitmap Graphic file format is free from patents and so many different programs provide support for opening and writing to the format.

This means that most graphics programs like Paint and Photo Viewer in Windows, IrfanView, XnView, GIMP, and more advanced programs like Adobe Photoshop, Adobe Photoshop Elements, and Corel PaintShop Pro, can all be used to open BMP and DIB files.

Note: Since the .DIB file extension isn't as widely used as .BMP, I assume there may be some other non-graphics-related programs that use files that have a .DIB file extension. In that case, I suggest opening the DIB file as a text document with a free text editor to see if there's any text within the file that can be helpful in finding out what type of file it is and what program was used to create it.

Tip: If your BMP or DIB file isn't opening with these image viewers, it's possible that you're misreading the file extension. BML (Bean Markup Language), DIF (Data Interchange Format), DIZ, and DIC (Dictionary) files share common letters with DIB and BMP files but that doesn't mean they can open with the same software.

Considering the very wide support for the BMP/DIB format, you probably already have at least two, maybe several, programs installed that support files that end in one of these extensions. While it's great to have options, you probably prefer one program in particular for working with these files. If the default program that's currently opening BMP and DIB files is not the one you'd like to use, see How to Change File Associations in Windows for steps on what to do.

There are lots of free image converter programs that convert BMP files to other image formats like PNG, PDF, JPG, TIF, ICO, etc. You can even do so in your web browser with the online image converters FileZigZag and Zamzar.

Some BMP converters may not let you open a file that has the .DIB file extension, in which case you can use alternatives like CoolUtils.com, Online-Utility.org, or Picture Resize Genius.

If you're looking to create a .DIB file by converting a picture into the DIB format, you can do that with the free online AConvert converter.

See Get More Help for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what kinds of problems you're having with opening or using the BMP/DIB file and I'll see what I can do to help.