BMP to PNG Converter Free
Convert BMP bitmap images to PNG online for free. PNG is lossless — every pixel is preserved exactly. Supports transparency from 32-bit BMP files. Batch up to 20 files. No signup required.
Drop your BMP files here
or click to browse — BMP · DIB · up to 20 files free
BMP / DIB · Up to 20 files · Max 200 MB total free
0 BMP file(s) selected
Conversion Options
No account required · Files deleted in 24h
Converting BMP to PNG…
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Files
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Input size
PNG
Output format
Pro — 200 files/batch, 2 GB, 16-bit PNG output, metadata preservation
API access · Priority queue · Team workspace
How It Works
Convert BMP to PNG losslessly in three steps
Upload BMP Files
Drag and drop your BMP or DIB files onto the upload zone, or click to browse. Supports all BMP colour depths from 1-bit monochrome up to 32-bit RGBA. The free plan handles up to 20 files at a time with a 200 MB total upload limit.
Set PNG Options
Choose PNG compression level (higher = smaller file, longer to compress), whether to preserve transparency from 32-bit BMPs, and an optional maximum output dimension. PNG compression is lossless — quality never degrades regardless of compression level chosen.
Download PNG Images
Your PNG files are ready in seconds. Unlike BMPs, PNGs are universally supported in every web browser, design tool, and image editor. They are significantly smaller than BMP while being completely lossless — making them perfect for graphics, logos, screenshots, and diagrams.
BMP to PNG Features
Lossless bitmap conversion with full format support
100% Lossless Conversion
PNG uses DEFLATE lossless compression — every pixel in your BMP is preserved exactly as-is in the output PNG. There is zero quality degradation, no compression artefacts, no blurring of edges, and no colour shifts. The output PNG is pixel-for-pixel identical to the source BMP. This makes BMP to PNG ideal for screenshots, technical diagrams, logos, and artwork with flat colours or sharp edges.
Full Transparency Support
32-bit BMP files contain an 8-bit alpha channel encoding per-pixel transparency. Our converter reads this alpha data and passes it through to the PNG output, producing a full RGBA PNG. The resulting PNG will display with correct transparent regions on any web browser or image viewer that supports PNG transparency. 1-bit monochrome BMPs can also have a transparent colour mapped to PNG transparency.
All BMP Colour Depths
The converter handles every BMP variant: 1-bit (monochrome, black/white), 4-bit (16-colour paletted), 8-bit (256-colour paletted), 16-bit (high colour, 5-6-5 or 5-5-5 RGB), 24-bit (true colour), and 32-bit (true colour with alpha). Palette-indexed BMPs are correctly expanded and palettes are preserved in the PNG output as indexed colour where possible to keep file sizes minimal.
Batch — 20 Files at Once
Convert up to 20 BMP files simultaneously. Batch results are packaged into a ZIP archive with file names preserved (extension changed to .png). This is especially useful for bulk-converting BMP exports from legacy Windows software, scanned document archives, or screenshot collections captured with older tools that default to saving as BMP.
Significant File Size Reduction
Despite being lossless, PNG is dramatically smaller than BMP. A 24-bit BMP screenshot is stored uncompressed at ~3 bytes/pixel; the same screenshot as PNG typically compresses to 20–50% of that size using DEFLATE compression. For photographic content, the reduction is smaller (PNG doesn't beat BMP by as much for photos — use JPEG for those). For screenshots and graphics, PNG saves 50–80% vs BMP.
Secure & Private
All uploads are encrypted with TLS 1.3. Files are processed in isolated server containers with no cross-user data access. Uploaded BMP files and converted PNGs are permanently deleted within 24 hours. No watermarks are ever added to converted images. No account or login is required — start converting immediately without creating a profile.
Free vs Pro
| Feature | Free | Pro |
|---|---|---|
| Files per batch | 20 | 200 |
| Max total upload size | 200 MB | 2 GB |
| PNG compression level | 3 presets | 0–9 slider |
| 16-bit PNG output | — | |
| Metadata / tEXt chunk preservation | — | |
| API access | — | |
| Priority conversion queue | — | |
| Watermark | None | None |
Frequently Asked Questions
PNG is lossless — it preserves every pixel exactly like BMP does, but with dramatically better compression for many image types. Use PNG (not JPEG) when your image contains sharp edges, flat colours, text, logos, diagrams, or screenshots — content where JPEG compression artefacts would be clearly visible as blurring and blocky ringing around edges. PNG also supports transparency, which JPEG does not. For photographic images without sharp edges, JPEG is a better choice due to its much higher compression ratio.
Yes, when the input is a 32-bit BMP. 32-bit BMPs store an 8-bit alpha channel (BGRA format). Our converter reads this alpha and outputs a full 32-bit RGBA PNG, preserving all transparency including semi-transparent pixels. Enable "Preserve transparency (alpha channel)" in the options — it is on by default. Note that 24-bit BMPs have no alpha channel, so the PNG output will be fully opaque (no transparent areas).
It depends heavily on the image content. Screenshots and diagrams with large areas of flat colour compress extremely well — expect 60–80% reduction (e.g. a 6 MB BMP screenshot becomes a 600 KB–1.2 MB PNG). Complex photographic content compresses less efficiently — you might see 20–40% reduction. Monochrome 1-bit BMPs compress spectacularly to tiny PNGs. In every case, PNG will be noticeably smaller than BMP while being 100% lossless.
PNG uses the DEFLATE algorithm, which offers compression levels 0–9. Level 1 is fastest but produces the largest PNG file. Level 9 takes longest but produces the smallest possible file. Level 6 is the standard compromise. Critically, all levels are lossless — the image quality is identical regardless of the level chosen; only the file size and conversion time differ. For most use cases, level 6 (the default) is the best choice.
Yes. The free plan supports up to 20 BMP files per conversion batch. Select all the files at once using Ctrl+click (Windows) or Cmd+click (Mac) in the file picker, or drag multiple files at once onto the upload zone. When converting multiple files, the results are packaged into a ZIP archive for download. Pro subscribers can convert up to 200 files per batch.
Yes. All uploads use TLS 1.3 encryption. Files are processed in isolated server containers and permanently deleted within 24 hours. No watermarks are added to any converted images. We never view, share, or retain your images. No account is required.