What Are BMP and DIB Files?

This is an image format supported by most graphics programs

By
Tim Fisher
Photo of Tim Fisher, Lifewire GM and Writer
Tim Fisher
Senior Vice President & Group General Manager, Tech & Sustainability
  • Emporia State University

Tim Fisher has more than 30 years' of professional technology experience. He's been writing about tech for more than two decades and serves as the SVP and General Manager of Lifewire.

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Updated on February 13, 2023

What to Know

  • A BMP file is a Device-Independent Bitmap (DIB) graphic file.
  • Lots of image viewers and editors support the format, like Windows Photos and Apple Photos.
  • Convert one to JPG, PDF, PNG, etc., at Zamzar, or with Filestar.

This article describes what BMP and DIB files are, plus how to open or convert one.

What Are BMP and DIB Files?

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, they can optionally become smaller through lossless data compression.

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

BMP files in Windows 10

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

DIB and BMP files aren't truly identical because the two have different header information.

How to Open a BMP or DIB File

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

This means that most graphics programs can be used to open BMP and DIB files. This includes Photos and Paint in Windows, as well as IrfanView, XnView, GIMP, and more advanced programs like Adobe Photoshop and Corel PaintShop Pro.

Apple Preview, Apple Photos, and ColorStrokes can open BMP files on macOS.

Since the .DIB file extension isn't as widely used as .BMP, we assume there may be some other non-graphics-related programs that use files that have a .DIB file extension. In that case, we suggest opening the 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.

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. See How to Change File Associations in Windows to change which program opens when you double-click the image.

How to Convert a BMP or DIB File

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 Online-Utility.org, Filestar, 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.

Still Can't Open It?

If your file isn't opening with these image viewers, it's possible that you're misreading the file extension.

BML (Bean Markup Language), BMF (FloorPlan), DIF (Data Interchange Format), DIZ, DB, and DIC (Dictionary) files share common letters with DIB and BMP files, but that doesn't mean they can open with the same software.

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