BMP is Windows' basic bitmap that stores pixels as they are, without compression. BMP opens in most environments, but another format such as PNG may suit some uses better.
PNG is a versatile lossless format with transparency support. When you convert BMP to PNG, you can open it in more places, the file gets smaller and you get a format that supports transparency. See the comparison below for what changes.
This converter reads the file itself to confirm it is BMP, then converts it to PNG right in your browser. Your image is never uploaded.
BMP vs PNG: what's the difference?
| Item | BMP | PNG |
|---|---|---|
| Compression | None (uncompressed) | Lossless |
| Transparent background | No | Yes |
| Animation | No | No |
| Introduced | 1990 | 1996 |
| Support in programs and upload forms | broad | nearly everywhere |
| Shown directly in browsers | Yes | Yes |
| Photo file size (JPG = 1) | about 12× | about 3× |
What is BMP?
BMP is a bitmap format from Windows that mostly stores pixel values as they are, without compression. Its simple structure makes it easy for programs to read, but the files are so large that it is rarely used on the web.
What is PNG?
PNG (Portable Network Graphics) is a lossless format created in 1996 to avoid the patent problems around GIF. Because not a single pixel changes when you save and reopen it, it suits original artwork that goes through many edits.
What changes when you convert BMP to PNG
Converting doesn't add a transparent background
BMP has no transparency information, so converting to PNG keeps the background as it is. To remove a background you need a separate background-removal tool.
Pixel values are preserved exactly
BMP and PNG are both lossless, so there is no change in quality. Only the file structure, compatibility and size differ.
PNG has no quality setting
PNG is lossless, so the quality slider doesn't apply. Instead, when converting from BMP you can manage file size by resizing (exact width and height, or a percentage).
How the file size changes
PNG is far smaller than BMP (roughly 1/4 the size). This is for photos; for simple images such as logos and screenshots, PNG can actually come out smaller.
PNG opens in more places
Support for BMP in programs, document tools and upload forms is broad, while PNG is nearly everywhere. If you need to upload somewhere BMP wouldn't open, try again after converting.
When to convert
- You need to upload to a program, messenger or upload form that can't open BMP
- You need to shrink a BMP file for an email attachment or an upload size limit
- You're preparing an image for typical PNG uses (logos and icons, screenshots)
BMP → PNG: practical tips
Like BMP, PNG has no quality loss, but the file is much smaller. If you want to keep the quality and only reduce the size, PNG is a better fit than JPG.