Drag & drop your .bmp files here — convert many at once — or click to choose
What is BMP, and why convert it?
BMP is the bitmap format Microsoft built into Windows in the late 1980s, and it has barely changed since. Its whole design philosophy is simplicity: the file is essentially a header followed by the colour value of every pixel, written out in order with no compression at all. That makes a BMP trivially easy for a program to read, which is why scanners, screen-capture utilities, mapping tools and old line-of-business software still hand them out. The downside is weight. Because nothing is packed down, a single desktop-sized image can occupy tens of megabytes, and a folder of them can swallow a hard drive in no time. Modern apps, browsers and phones would much rather work with a compressed format, so moving those bitmaps to PNG keeps them faithful while making them far more practical to store and open.
Why convert BMP to PNG?
PNG is the natural home for a bitmap because, like BMP, it is lossless — it reproduces every pixel exactly — but it wraps that data in efficient compression. You keep the original quality and gain a much smaller, more portable file. Choosing BMP → PNG gives you:
- No quality loss at all: PNG rebuilds the image pixel-for-pixel, so a converted screenshot or diagram is indistinguishable from the source.
- Dramatically smaller files: the same picture often drops to a fraction of the BMP size, with the biggest savings on flat colour, text and line art.
- Transparency support: PNG carries an alpha channel, so you can keep or add transparent areas that plain BMP cannot store.
- Works everywhere: every browser, editor and chat app opens PNG instantly, unlike heavy bitmaps that some tools refuse to preview.
If the image is a photograph and you care more about getting the smallest possible file than about staying lossless, BMP to JPG will compress it further.
BMP vs PNG
| Format | Compression | Quality | Typical file size | Transparency |
|---|---|---|---|---|
| BMP | None (raw pixels) | Lossless | Very large | Rarely supported |
| PNG | Lossless (zlib) | Lossless | Much smaller | Yes (alpha channel) |
How to batch convert BMP to PNG
- Drag your .bmp bitmaps into the box above, or click it to select a whole folder at once.
- Each file is decoded in your browser and re-saved as a lossless PNG — there is no quality slider, because PNG keeps every pixel automatically with nothing to trade away.
- Download each PNG individually, or click Download all to grab the whole batch as one ZIP. Your files never leave your device.
Common jobs this tool helps finish
- Archiving legacy bitmap libraries so they take up a fraction of the space without losing a single pixel.
- Cleaning up scanner or capture output that saved diagrams and screenshots as bulky BMP files.
- Preparing graphics for the web or a document where editors expect PNG rather than raw bitmaps.
- Keeping a lossless master of a logo or UI mockup that you'll edit again later.
Is it private?
Yes. Each bitmap is decoded and re-saved entirely inside your browser, so your images are never uploaded to a server and never stored by us. Most online converters send your files to a remote machine to process them — this one doesn't, which matters when those bitmaps are scanned documents or work-in-progress designs.
Related converters
Need the smallest possible file for a photo instead of a lossless copy? Use BMP to JPG. Working with other formats? Try PNG to JPG to shrink the PNGs you create here, or JPG to PNG for a lossless working copy.
Frequently asked questions
Will I lose any quality converting BMP to PNG?
No. Both BMP and PNG are lossless, so the PNG is a pixel-perfect copy of the bitmap — only the file size changes.
Why is the PNG so much smaller than the BMP?
BMP stores every pixel raw with no compression, while PNG applies lossless compression. The result is identical image data in a much smaller file, with the biggest savings on flat colour and text.
Does PNG keep transparency from the bitmap?
PNG fully supports an alpha channel, so any transparency is preserved and you can add transparent areas later. Most plain BMP files are opaque, but the channel is there when you need it.
Can I batch convert a folder of BMP files?
Yes. Add as many BMP files as you like, convert them in one batch, and download them all as a ZIP. Large uncompressed bitmaps use a lot of memory, so very big batches run best on a desktop.
Are my images uploaded to a server?
No. Conversion runs entirely in your browser, so your bitmaps never leave your device and are never stored by us.