Convert BMP to PNG
PNG gives you the same lossless fidelity as BMP but with proper compression, so files are typically 2–5× smaller. It's the right modern replacement for BMP whenever you need pixel-perfect images.
To convert BMP to PNG, drop your bitmap above and download the PNG. PNG is lossless like BMP but uses DEFLATE compression, so the file is typically 50–80% smaller with pixel-identical output. Ideal for scanned documents, retro pixel art, and any place you want to keep a BMP's exact fidelity without wasting disk space. This is the conversion to prefer over BMP to JPG whenever the image contains text, line art or sharp edges, because nothing is approximated — every pixel in the PNG matches the BMP exactly, and a later conversion to any other format starts from an unspoiled source. Compression ratios depend heavily on content: a screenshot with large flat areas can shrink by 90 percent, while a noisy photograph stored as BMP may only drop 30 to 40 percent, since DEFLATE has little repetition to exploit.
Drop a BMP here, or click to upload
Output: PNG
What happens when you convert BMP to PNG?
BMP stores raw RGB pixel data with no compression, while PNG stores the same pixels with lossless DEFLATE. That is why the conversion is safe for pixel-critical work: every pixel value is preserved, only the on-disk encoding is smarter. PNG also supports optional gamma and color-profile tags, so long-term archives are more colour-manageable than BMP. Software developers converting retro-game sprite sheets, GIS tools converting map raster tiles, and scanner users converting document archives all benefit from the lossless size reduction.
Common mistakes and limitations when going from BMP to PNG
PNG has no built-in support for BMP's rare metadata quirks (some scanner-specific chunks are dropped). Extremely large BMPs — over 100 MP — take noticeable time to encode because DEFLATE is single-threaded in the browser. And while PNG supports 16-bit-per-channel data, canvas re-encoding only exposes 8-bit; if you have a scientific BMP with genuinely deeper color, use a dedicated 16-bit-aware tool.
Choosing the right settings for BMP to PNG
This is the safe default for BMP conversion. PNG is lossless, so every pixel is preserved exactly, and its compression typically reduces an uncompressed BMP by 50 to 80 percent depending on content — flat interface graphics compress dramatically, photographic content less so. Because nothing is discarded, this conversion is reversible in practice: the PNG can be converted back to BMP with identical pixel data. That makes it the right choice for archival, for content that will be edited further, and for anything where the BMP is a master file rather than a delivery format. BMP is most often encountered as output from screen capture on older Windows systems, from scanners, and from scientific and industrial instruments. All of that content — screenshots, scanned documents, instrument plots — is exactly what PNG handles best, with large areas of flat colour and sharp text that lossless compression handles efficiently and lossy compression damages. The one case for choosing JPG instead is a genuine photograph destined for the web where file size dominates. Everything else should go to PNG. If the BMP is a 32-bit variant carrying an alpha channel, PNG preserves it, which JPG cannot. One quirk worth knowing is that BMP stores rows bottom-up by default, and a small number of older tools write the row order flag incorrectly. If a converted PNG appears vertically flipped, the source file is malformed rather than the conversion being wrong; re-exporting the BMP from its originating application usually resolves it. Colour depth is the other thing to check. BMP exists in 1, 4, 8, 16, 24 and 32-bit variants, and the low-depth ones are palette-based like GIF. Converting an 8-bit palette BMP to PNG preserves exactly the 256 colours present — it does not restore colour the palette never held, so banding in the source stays banded in the output. If the original scan or capture is still available at a higher bit depth, converting that instead will give a materially better PNG than upgrading an already-reduced file.
BMP to PNG conversion FAQ
Is PNG truly lossless?
- Yes. Every pixel value in the BMP is copied into the PNG exactly — only the on-disk encoding changes.
Does PNG preserve BMP transparency?
- Standard BMPs are opaque, so the PNG will be opaque too. Rare BMPv5 alpha data is preserved.
How much smaller will the PNG be?
- Usually 50–80% smaller than the BMP, depending on image content. Flat graphics compress the most; noisy photos the least.
Can PNG replace BMP everywhere?
- For nearly all modern uses, yes. The only holdout is legacy Windows or industrial software that specifically requires BMP input.
Does the PNG open in old software?
- PNG has been universally supported since 1996 — every browser, editor, mobile OS and word processor reads it.
What about 16-bit-per-channel BMPs?
- The browser canvas API is limited to 8 bits per channel, so genuine 16-bit scientific data will be down-sampled. Use a dedicated tool for those.
Will scanned documents stay sharp?
- Yes — DEFLATE is lossless, so text edges and fine strokes are preserved exactly.
Can I convert very large BMPs?
- Files up to 100 MB are supported. Very large images take a few seconds to encode in-browser.
BMP vs PNG at a glance
| Property | BMP source | PNG output |
|---|---|---|
| Compression | None | Lossless DEFLATE |
| Typical size (12 MP image) | 35–75 MB | 8–20 MB |
| Transparency | Rare (BMPv5 only) | Yes (8-bit) |
| Compatibility | Windows-first | Universal |
| Best used for | Legacy Windows workflows | Modern lossless archive |
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References: Microsoft BMP File Format specification, ISO/IEC 15948 (PNG), libpng documentation on DEFLATE efficiency for bitmap sources.