A screenshot saved as BMP
The best case for this conversion. Large flat areas compress dramatically, often to a tenth of the size, with the text still pixel-perfect.
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Use BMP to PNG
Your image is decoded and re-encoded on this device. No upload request is made.
PNG preserves transparent pixels and uses lossless encoding.
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Browse all image toolsAbout BMP to PNG
This is the conversion to choose when the image must not change at all. PNG is lossless, meaning every pixel is reproduced exactly as the BMP held it, and yet the file is usually far smaller - often a fifth of the size or less. That sounds contradictory until you consider what BMP actually does, which is almost nothing: it writes each pixel out one after another with no attempt to notice that a large area of a screenshot is the same shade of grey. PNG applies real lossless compression to exactly that redundancy. So unlike the JPEG route, there is no trade being made here. You get an identical image in a smaller file, and it stays editable indefinitely without accumulating compression artifacts each time it is saved.
Shape and export choices
- The BMP is decoded to raw pixels, including any alpha channel a 32-bit variant carries.
- A canvas with transparency enabled is created at the original dimensions, so nothing is composited onto a background.
- The pixels are encoded as PNG. There is no quality setting because the encoding is lossless and nothing is discarded.
- The compression works on runs of identical or similar pixels, which is why screenshots and diagrams shrink the most.
- Dimensions, colours and transparency are all identical to the source; only the file size changes.
Good fits for BMP to PNG
An image that will be edited repeatedly
PNG can be opened and saved any number of times without degrading, which a JPEG cannot.
Check the image before download
- For photographs, PNG will be considerably larger than JPEG. Lossless storage of continuous tone is expensive, and JPG is the better choice when exactness is not required.
- A very noisy or grainy image compresses poorly, because there is little redundancy for the algorithm to exploit.
- Older BMP variants using RLE compression or uncommon bit depths may fail to decode in a browser.
- PNG has no concept of the physical print size some BMP headers record, so that metadata is not carried across.
- The image is not improved. Lossless means unchanged, not enhanced.
Questions about BMP to PNG
Is any quality lost?
None. PNG is lossless, so the pixels are identical to the BMP.
Why is it so much smaller then?
Because BMP performs essentially no compression while PNG performs real lossless compression. The picture is the same; the storage is far more efficient.
PNG or JPG for my BMP?
PNG for screenshots, diagrams and anything to be edited. JPG for photographs where a much smaller file matters more than exactness.
Does transparency survive?
Yes. A 32-bit BMP with an alpha channel keeps it, since PNG supports transparency properly.
Does the file leave my device?
No. Everything runs in this tab.
Related tools
BMP to JPG
Convert a BMP to JPG in your browser. BMP files are uncompressed, so the saving is usually enormous.
BMP to WebP
Convert BMP to WebP in your browser for the smallest file of the three options, with transparency preserved.
PNG to JPG
Convert PNG to JPG locally in your browser. Transparent pixels are placed on white, dimensions stay unchanged, and the image is never uploaded.