How do I open a BMP file on Windows?

BMP opens in the built-in Photos app, classic Paint and any browser. For editing, use Paint.NET, GIMP or Photoshop. On Windows the format is supported out of the box — nothing to install.

How do I open BMP on a phone?

On Android BMP usually opens in the default gallery or Google Photos. On iPhone the built-in viewer does not always show BMP — the easiest fix is to convert it to JPG with an online converter right in the phone's browser, and the file will open anywhere.

How do I reduce the size of a BMP?

The most reliable way is to convert BMP to a compressed format. For graphics choose PNG (lossless), for photos JPG (smallest size). That makes the file 5–10 times lighter with no noticeable loss of quality.

Will quality drop if I convert BMP to PNG?

No. PNG compresses losslessly, so the image stays exactly as it was in the original BMP — the file just takes up less space.

Is it safe to convert BMP online?

On FormatZ files are sent over a secure HTTPS connection and are automatically deleted from the servers two hours after conversion. The contents of files are not stored or analyzed.

How to Open BMP and Shrink Its File Size

Someone sent you a .bmp file and your phone refuses to show it? Or a screenshot ballooned to 30 megabytes and is awkward to share? This guide solves both problems: first we open BMP on any device, then we make it many times lighter — quickly, for free and with no quality loss.

The fastest way

If you have no time for the whole article, here is the short answer. To open a BMP, just double-click it on almost any Windows computer — the format is supported by the system by default. To shrink it, conversion is easiest: upload the BMP to an online converter and save it as PNG (for graphics) or JPG (for photos). The file becomes 5–10 times lighter. Everything else in this article is detail for specific devices and situations.

Tip

If you only need to look at the file, open it with anything. If you plan to share it, email it, upload it to a site or store it in the cloud — convert it right away: BMP is needlessly heavy for those tasks.

How to open BMP on Windows

Windows and BMP are family: the format was created by Microsoft, so it opens out of the box with no installs. Here are the main options:

The Photos app. The standard viewer in Windows 10 and 11. Just double-click the file.
Paint. The classic program that will not only show a BMP but also let you tweak it and re-save it to another format.
Any browser. Drag the .bmp into a Chrome, Edge or Firefox window — the picture opens like a regular web page.
File Explorer. In large-icon view, Windows shows a BMP thumbnail right in the folder.

On Windows the problem is rarely opening the file — it is the weight. So let's get to the main part, but first let's cover other devices.

On Mac, Android and iPhone

Outside Windows, BMP support is not as smooth. Here is what matters:

macOS. The built-in Preview app opens BMP without trouble and can export straight to PNG or JPG via "File → Export."
Android. Most galleries and Google Photos display BMP. If some app is stubborn, converting to JPG helps.
iPhone and iPad. This is where trouble most often arises: the built-in iOS viewer does not always get along with BMP. The most reliable fix is to open an online converter right in Safari, turn the BMP into JPG and save it to Photos.

A row of vintage monitors with different images — different devices handle BMP differently — Different devices open BMP differently. The universal fix is to turn it into JPG or PNG. Photo: Pexels

How to edit BMP

If the goal is not just to view but to edit the picture — crop it, add a caption, fix the colors — any graphics editor will do:

Paint.NET — free, lightweight, ideal for quick edits on Windows.
GIMP — a free, powerful editor for every platform, a Photoshop alternative.
Adobe Photoshop — the professional standard; opens and saves BMP without issue.

One important point: after editing, do not save back to BMP unless you have a specific reason. Choose PNG or JPG — the result will match in quality but be many times smaller in weight.

How to shrink it: PNG or JPG

BMP's main pain point is weight. A screenshot can take 20–40 MB, a photo a full 50. There is one fix: convert it to a compressed format. The choice between PNG and JPG depends on what is in the picture.

What's in the picture	Best format	Why
Photograph	JPG	Smallest size, loss invisible on photos
Screenshot, text	PNG	Sharp edges and letters stay crisp
Logo, graphics	PNG	Lossless, supports transparency
Need transparency	PNG	JPG cannot do transparency

−70%PNG typically gives

−90%JPG gives and more

0loss with PNG

Conversion in 3 steps

An online converter needs no install and works the same on a computer and a phone. The whole process takes under a minute:

Upload the BMP

Open the converter and drag your .bmp into the window, or pick it with the button.

Wait for processing

The file turns into a PNG in a couple of seconds — quality is preserved in full.

Download the result

The finished PNG is many times lighter and opens on any device, iPhone included.

Open and shrink your BMP right now

The free FormatZ converter turns a heavy BMP into a compact PNG in a couple of seconds — in your browser, with no install and no sign-up.

Convert BMP to PNG

If the file is a photo, converting BMP to JPG is more efficient — the weight drops the most. Need a different format? Check the all formats page.

Common mistakes

A few typical slip-ups that are easy to avoid:

Watch out for

1. Saving text and screenshots as JPG. Blurry halos appear around letters — use PNG for that content.
2. Keeping the file as BMP "just in case." It will take up many times more space for no benefit.
3. Changing only the extension by hand. Renaming .bmp to .png in Explorer will break the file — you need an actual conversion.

A vintage Macintosh with pixel art on screen — the kind of image best kept as PNG — Pixel art and screenshots fit PNG perfectly — lossless and many times lighter than BMP. Photo: Pexels

Opening a BMP takes seconds. What matters far more is not leaving it at that weight: one click of conversion saves tens of megabytes.