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PNG to BMP Converter
Convert a PNG into a Windows BMP bitmap. Every pixel stays exactly the same — both formats are lossless — but three things are removed: compression, transparency and text metadata. How much the missing compression costs depends almost entirely on what the image is, and the range is startling: a photograph grew by 21% in testing; a simple graphic grew 278 times.
Drag and drop your PNG images here
Add several at once. Each file is processed and then deleted from our server.
Up to 20 MB per file Batch ready
BMP cannot store transparency, so it is filled with this colour.
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Step by step
How to convert PNG to BMP in 3 steps
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Add your PNG
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Choose a background colour
Choose a background colour if your PNG has transparent areas. It becomes part of the image permanently.
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Download your BMP
Format comparison
PNG vs BMP
PNG (Portable Network Graphics)
LosslessStores every pixel exactly as it was saved, so nothing is lost however often the file is opened and saved.
- Pixel-perfect: ideal for screenshots, logos and text
- Supported everywhere, including every browser
- Photographs make large files — often several times the JPG size
BMP (Windows Bitmap)
UncompressedAn early Windows format that stores pixels more or less raw, with little or no compression.
- Read by old and embedded software that knows nothing newer
- No compression artefacts
- Very large files for the image size
A PNG is, roughly, a compressed BMP with extras
Underneath, both formats describe the same thing: a grid of pixels, stored exactly. PNG adds three layers on top, and converting to BMP strips them away.
- Lossless compression. PNG finds patterns in the pixels and stores them compactly. BMP stores every pixel raw.
- Transparency. PNG has a full alpha channel with 256 levels. A standard BMP has none.
- Metadata. PNG can carry text, creation details and other annotations. BMP has no place for them.
Why the size change varies so much
PNG's compression works by spotting repetition. How much repetition an image has decides everything.
A simple graphic — a logo, an icon, a diagram, an interface — is mostly large areas of identical colour, which PNG compresses to almost nothing. Remove the compression and the file jumps to its full raw size. Measured: a 600 × 400 graphic went from 2.6 KB to 720 KB.
A photograph has almost no exact repetition — every pixel differs slightly from its neighbours — so PNG could barely compress it in the first place. Removing compression that was not achieving much costs little. Measured: a photo PNG went from 299 KB to 361 KB.
So the images that suffer most from this conversion are the ones people most often keep as PNG.
Transparency becomes your background colour
Transparent and partly-transparent areas are blended onto the colour you choose, and the result is a solid image. A soft shadow fades into that colour correctly — it does not gain a hard edge — but it is now part of the picture and cannot be separated again.
Choose the colour the image will actually sit on. Anything else leaves a visible rectangle, and a faint halo of the wrong colour around soft edges.
What happens to transparent pixels when converting PNG to BMP?
BMP cannot store transparency, so transparent and semi-transparent areas are blended onto a solid background before the file is saved — the colour you choose above, #FFFFFF by default. Keep your original PNG if you may need the transparency again.
Quality
Quality and file size
There is no quality setting. Both formats are lossless, so apart from transparency being flattened the pixels are identical.
Why the colour choice matters more for BMP than elsewhere
The software that needs BMP is usually old, and old software commonly mishandles transparency in bitmaps — sometimes ignoring it, sometimes showing what was behind it as black. Flattening onto an explicit colour avoids that: what you choose is exactly what appears, in any program.
Game engines and colour keys
Some older engines and sprite tools treat one specific colour in a bitmap as "transparent" —
often bright magenta, #ff00ff. If yours does, set that as the background colour and
your PNG's transparent areas will be recognised when the bitmap loads.
Be aware this only works for fully transparent areas. Soft, partly-transparent edges blend with the magenta and become pinkish pixels the engine does not treat as transparent — a pink fringe around your sprite. Sprites meant for colour-key engines should have hard edges.
Row padding and odd widths
BMP stores each row of pixels padded to a multiple of four bytes, so an image whose width is not a multiple of four carries a few invisible padding bytes per row. It changes nothing about the picture and very little about the size — but it is why a BMP is occasionally a handful of kilobytes larger than width × height × 3 would suggest.
When BMP is the right target
- Legacy Windows applications that only open bitmaps.
- Embedded displays and controllers without a PNG decoder.
- Older game engines, level editors and modding tools, often with colour-key transparency as described above.
- Installer graphics — setup banners and dialog images in some installer systems still require BMP.
- Raw-pixel processing in scientific or industrial software.
For anything else, keep the PNG. There is nothing BMP does better, and several things it cannot do at all.
Check the size before a batch
Because a bitmap's size is width × height × 3 bytes regardless of content, a folder of small, efficient PNG icons can become hundreds of times larger. A 1920 × 1080 screenshot is about 6.2 MB as BMP whatever it shows.
Going the other way
BMP to PNG is the more common need, and one of the best conversions available: nothing is lost, and the file typically shrinks dramatically.
What happens to your file
Browsers cannot write BMP files, so this runs on our server. Your upload is deleted the moment conversion finishes, the result is deleted as you download it, and anything abandoned is swept automatically.
Privacy
What happens to your file
This tool runs on our server, so it works the same on every phone and computer. Your file is uploaded, and this is exactly what happens to it:
- Stored outside the public web root under a random name, never under your file's name.
- Processed, with the original upload deleted immediately — whether it succeeded or failed.
- The result sits behind a signed link that only you receive, which stops working after 20 minutes, and the file is deleted the moment you download it.
- Anything never collected is deleted automatically within 30 minutes.
- The image itself is never logged or kept. If a conversion fails, we record the formats involved and the error — not the file.
- Camera metadata, including any GPS coordinates recording where a photo was taken, is removed from the result. Only the rotation needed to show the image the right way up is kept.
Questions & answers
PNG to BMP: frequently asked questions
Does converting PNG to BMP lose quality?
No — both formats are lossless, so the pixels are identical. What is lost is compression, transparency (flattened onto a background colour you choose) and metadata such as colour profiles.
Why did my small PNG become huge?
Because it is probably a simple graphic, which PNG compresses to almost nothing. A BMP stores every pixel raw, so the file jumps to full size: a 600 × 400 graphic went from 2.6 KB to 720 KB in testing. A photo PNG grows far less — 21% measured — because PNG could barely compress it in the first place.
What happens to transparent areas?
They are blended onto the background colour you choose and become part of the image permanently. Soft shadows fade into that colour properly rather than gaining a hard edge. Choose the colour the image will sit on, or you will see a rectangle and a faint halo.
My game engine uses magenta as the transparent colour.
Set the background to that exact colour, usually #ff00ff, and fully transparent areas will be recognised. Soft, partly-transparent edges blend into pinkish pixels the engine will not treat as transparent, so sprites for colour-key engines should have hard edges.
Why not just keep the PNG?
You should, unless software specifically requires BMP. PNG is smaller, supports transparency and metadata, and loses nothing. BMP is for legacy applications, embedded displays, old game tooling and some installer systems.
How large will my BMP be?
Width × height × 3 bytes, plus a small header, whatever the image contains. A 1920 × 1080 screenshot is about 6.2 MB. Rows are padded to a multiple of four bytes, so odd widths add a few kilobytes.
Keep going
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