BMP to PNG Converter
Convert BMP images to PNG format. Keep full quality with lossless compression while dramatically reducing file size. Batch supported.
BMP vs PNG: what changes
- PNG files are usually much smaller than BMP, so this is a good way to save space or speed up a page.
- Converting to PNG gives you transparency support, though this conversion won't recover any transparency that BMP already discarded.
- BMP stores pixels with no compression at all, resulting in very large files. Converting to PNG significantly reduces file size.
| BMP | PNG | |
|---|---|---|
| Full name | Bitmap Image File | Portable Network Graphics |
| Type | raster | raster |
| Compression | none | lossless |
| Transparency | No | Yes |
| Animation | No | No |
| Best for | raw/uncompressed, legacy systems | graphics, logos, screenshots |
| Browser support | universal | universal |
Written by Anil Gautam · Updated
Why does a BMP shrink so much as a PNG without losing quality?
A typical BMP stores every pixel raw: 3 bytes per pixel for 24-bit color, rows padded to a multiple of 4 bytes and a 54-byte header. At 1024 × 768 that comes to 1024 × 3 × 768 + 54 = 2,359,350 bytes, shown by the tool as 2.25 MB. PNG keeps the same pixels and compresses them losslessly with DEFLATE, the same method ZIP archives use, after a filter that predicts each byte from its neighbors. Runs of identical color, as in screenshots and diagrams, shrink to a small fraction of their raw size.
Photos and scans with fine grain compress much less, because almost every pixel differs from the one beside it. Older BMPs with an 8-bit palette start at 1 byte per pixel, so their saving is smaller. For photographs, BMP to JPG produces a far smaller file, at the cost of slight lossy changes.
What does the converter do with your BMP?
Your browser decodes the BMP, and the tool draws it at full size onto a blank canvas, then saves it with the browser's PNG encoder at the same width and height. There is no quality slider, because PNG output is lossless and the pixels you see are the pixels saved. Nothing is painted underneath, so if your browser reads transparency from a 32-bit BMP, the PNG keeps it. Each card shows the BMP size, the PNG size and, when the PNG is smaller, the percentage saved.
Converted files keep their names with a new extension, so diagram.bmp becomes diagram.png, and a batch downloads as bmp-to-png-converted.zip. Sizes on the cards count 1 KB as 1,024 bytes and 1 MB as 1,048,576 bytes, so they can look slightly smaller than the decimal figures some file managers show.
Should you convert a BMP to PNG or to JPG?
Choose PNG for screenshots, interface captures, charts, line drawings, pixel art and anything you will edit again, since every pixel survives exactly. If the PNG must be lighter for a web page, Image Compressor can reduce its colors; that step is lossy, though flat graphics with a few hundred colors usually keep them all. For photographs, start with BMP to JPG. Scanned documents can go either way: pages of text stay crisper as PNG, while scanned photos come out far smaller as JPG.