PNG to BMP Converter

Convert PNG to BMP directly in your browser, with no upload: the file bytes stay on your device and nothing is sent to a server. Most people land here because a downstream program demands a raw bitmap that the PNG will not satisfy, whether that is legacy Windows desktop software, an embedded microcontroller display, an industrial or POS system, or a game engine importing a development texture. You are not optimizing for the web here, you just need a file the other program will actually open.

What this conversion actually does (and does NOT do)

Both PNG and BMP are lossless formats, so converting PNG to BMP does not degrade pixel quality at all. The image looks pixel-for-pixel identical after conversion. What changes is not fidelity but two other things: transparency and file size. Understanding both up front saves you from the two complaints almost everyone has about BMP output.

The biggest gotcha is transparency, and it is irreversible. Standard 24-bit BMP has no concept of an alpha channel, so every transparent or semi-transparent pixel in your PNG must be flattened onto a solid background (white or black) during conversion. If your PNG had a transparent background, the BMP will not: that area becomes a flat fill, and soft anti-aliased edges or drop shadows get blended against the matte color. There is no way to recover the original transparency from the resulting BMP afterward.

The second surprise is size. PNG uses lossless DEFLATE compression, while BMP stores raw uncompressed RGB pixel data, so the BMP is typically 5-10x larger than the PNG it came from. A 1-2 MB PNG at 1920x1080 commonly balloons to roughly 6 MB as a 24-bit BMP. Counterintuitively, BMP size is fixed almost entirely by dimensions and bit depth (width x height x bytes-per-pixel plus a small header), not by image content, so a flat-color logo and a detailed photo of the same dimensions produce nearly identical BMP file sizes, which is never true for PNG. Internally, BMP rows are stored bottom-up and padded to 4-byte boundaries, a structural quirk that makes the format trivially fast to decode with zero decompression overhead, which is exactly why embedded devices and legacy apps favor it. This converter writes standard 24-bit BMP (16.7 million colors, no alpha), because some readers accept 32-bit BMP with an alpha channel but support is inconsistent across the old software that usually needs BMP in the first place.

When to choose PNG to BMP vs the alternative

Choose PNG to BMP when a target program demands raw bitmaps: legacy Windows software (BMP dates to Windows 3.0 in 1990, which is why it persists as a hard requirement in old desktop apps), embedded and POS displays, certain game-engine texture imports, or pixel-level editing workflows. Do not use BMP for anything web-facing, where it is strictly worse than the PNG you already have, both larger and without transparency. If you actually need to keep the alpha channel, do not convert at all; stay on PNG, and if you have a BMP that you want to bring back into a transparent-capable, compressed format, use BMP to PNG instead. To shrink a heavy PNG without changing format, the image compressor is the better tool.

How to convert

1. Drop one or many PNG files. They are read locally in the browser, with no upload.
2. The output format is pre-selected to BMP. There is no quality slider here, because BMP is uncompressed and lossless, so nothing about the pixels is thrown away.
3. Because 24-bit BMP has no alpha channel, any transparency is flattened against a solid background before encoding — plan for a white or black fill where the PNG was transparent.
4. Click Convert. A single file downloads directly; multiple files download as a ZIP, with no count cap.

No upload. It runs on your device.

The converter is compiled from Rust to WebAssembly and runs inside your browser tab. The PNG never leaves your machine, there are zero network requests for the file, and after the page loads once it works offline. There is nothing to delete afterward because nothing was ever sent, and you can confirm it yourself by opening the DevTools Network tab and watching it stay silent while you convert. This matters because the people who need BMP are disproportionately working on proprietary product art, medical or scientific images, and internal embedded assets they are contractually or ethically barred from uploading. As a bonus, since BMP output is so much larger than the PNG, converting locally also avoids uploading and then re-downloading a huge file over the network, so it is faster too.

No limits

Convert unlimited files in one batch, with no file-size or count cap, no watermark stamped on the output, no sign-up, and no ads. Server-based free tiers gate exactly these things; running locally removes the reason for the gate.

Frequently asked questions

Does converting PNG to BMP lose quality?

No. Both PNG and BMP are lossless formats, so the pixel data is preserved exactly and the image looks identical after conversion. The only things that change are transparency, which BMP cannot store, and file size, which grows because BMP is uncompressed.

What happens to transparency when I convert PNG to BMP?

Standard 24-bit BMP has no alpha channel, so every transparent or semi-transparent pixel is flattened onto a solid background color during conversion. This is irreversible: once the BMP is written, the original transparency cannot be recovered from it.

Why is my BMP file so much bigger than the PNG?

PNG uses lossless DEFLATE compression while BMP stores raw, uncompressed RGB pixel data, so the BMP is typically 5-10x larger. A 1-2 MB PNG at 1920x1080 commonly becomes roughly a 6 MB 24-bit BMP, and that size is set by dimensions and bit depth, not by how detailed the image is.

Is BMP higher quality than PNG?

No. Because both are lossless, a BMP made from a PNG contains exactly the same pixel quality, just stored uncompressed and without alpha. BMP is not sharper or more accurate; it is simply a rawer, larger container that legacy and embedded software can read with zero decompression overhead.

What color depth does the BMP output use, 24-bit or 32-bit?

This converter writes standard 24-bit BMP, which stores 16.7 million colors and no alpha channel. Some readers accept 32-bit BMP with alpha, but support is inconsistent across the legacy software that usually requires BMP, so 24-bit with transparency flattened is the safe, widely-compatible default.

Can I convert PNG to BMP without uploading my files?

Yes. The converter is compiled from Rust to WebAssembly and runs entirely inside your browser tab, so the PNG bytes never leave your device and there are zero network requests for the file. You can verify this in the DevTools Network tab, and the tool keeps working offline after the page has loaded once.

How do I batch convert multiple PNGs to BMP at once?

Drop as many PNG files as you like into the converter at the same time; there is no file-count or size cap. A single file downloads directly, and multiple files are packaged into a ZIP for one download, all processed locally on your machine.

Why would I need a BMP instead of a PNG?

BMP is a hard requirement in some legacy Windows desktop apps, industrial and POS systems, microcontroller display pipelines, and certain game-engine texture imports, because its uncompressed bottom-up rows decode instantly. If a program rejects your PNG and asks for a bitmap, BMP is what it wants; for anything web-facing, PNG remains the better choice.

Will the transparent background turn black or white in the BMP?

It becomes a solid fill (commonly white) wherever the PNG was transparent, since 24-bit BMP cannot store transparency. Semi-transparent and anti-aliased edge pixels are blended against that matte color, so soft edges and shadows will shift appearance depending on the background fill.

Can I convert the BMP back to PNG without losing anything?

You can convert the BMP back to PNG losslessly and the visible pixels will be identical, but the transparency that was flattened during the PNG-to-BMP step cannot be restored. The round trip recovers compression and the PNG container, not the original alpha channel.

Related tools: convert back with BMP to PNG, or browse all image tools for compression, resizing, and other format conversions.