Convert PNG to BMP
Output is typically roughly 2.6× larger.
- Files stay on your device
- Free, no sign-up
Related tools
All image toolsQuestions
Does the BMP keep transparency?
Yes, in this case. The output is a 32-bit BGRA bitmap with a V4 header, which carries explicit channel masks including alpha — so transparent and semi-transparent pixels are preserved exactly. Be aware that older software expecting a plain 24-bit BMP may ignore the alpha channel or, occasionally, refuse the file. If a legacy tool rejects it, flatten to a solid background first.
Will converting PNG to BMP make the file smaller?
Usually, yes. A 12-megapixel photo is around 14 MB as PNG and around 36 MB as BMP — roughly 2.6× larger. Because BMP is lossless the result depends entirely on the image content — flat colour and text compress far better than photographic detail.
Does converting PNG to BMP lose quality?
No. BMP is lossless, so every pixel decoded from your PNG file is stored exactly. Both formats are lossless, so the conversion is pixel-for-pixel identical.
Is transparency preserved when converting PNG to BMP?
Yes. Both PNG and BMP support an alpha channel, so transparent and semi-transparent pixels carry across unchanged — a logo with a cut-out background stays cut out, and soft drop shadows keep their gradient rather than picking up a white halo. Because BMP is lossless, the alpha channel is stored exactly as it was.
Why are BMP files so large?
BMP stores pixels essentially uncompressed — three or four bytes per pixel with no encoding at all. A 12-megapixel photo therefore lands around 36 MB, roughly 11× the same image as a JPEG. That simplicity is deliberate: legacy Windows software and embedded devices can read BMP with almost no code.
What kind of BMP does this produce?
An uncompressed 32-bit BMP with a BITMAPV4 header, which is the variant that carries an alpha channel reliably — plenty of BMP writers emit 24-bit files where transparency is silently dropped. Uncompressed means large: expect roughly four bytes per pixel, so a 12-megapixel photo lands around 48 MB regardless of what it started as.
How it works, and more about png to bmp
How it works
- Add your PNG file. Drag a PNG file onto the drop zone, or click to browse. You can select several at once.
- Choose your settings. BMP is lossless, so there is nothing to configure — the output matches the input pixel for pixel.
- Download the BMP. Conversion runs on your device as soon as each file is added — no upload, no queue. Download each result when it is ready.
Why people convert PNG to BMP
Feeding something that wants raw pixels: a legacy Windows application, an embedded display, a microcontroller project, or a test fixture that needs a predictable uncompressed file.
Straightforward, and the output is more capable than most BMP writers produce — 32-bit BGRA with a BITMAPV4HEADER, so the alpha channel survives rather than being flattened. That matters if the thing consuming it understands modern BMP variants.
Worth knowing: The file will be enormous, because BMP applies essentially no compression — expect roughly four bytes per pixel regardless of what the image contains.
PNG and BMP side by side
| PNG | BMP | |
|---|---|---|
| Full name | Portable Network Graphics | Bitmap Image File |
| Compression | Lossless | Lossless |
| Transparency | Yes — alpha channel | Yes — alpha channel |
| Animation | No | No |
| Browser support | Universal — every browser since 1996 | Supported in all major browsers, though rarely used on the web |
| Typical 12 MP photo | ~14 MB | ~36 MB |
| Usually used for | Screenshots, logos, icons, diagrams and anything needing transparency | Legacy Windows applications, scanners and embedded displays |
On a typical 12-megapixel phone photo, the BMP output comes out roughly 2.6× larger than the PNG original. These are order-of-magnitude figures for one kind of image — your own results will vary a great deal, because flat colour, text and line art behave nothing like photographic detail.
What this tool actually produces
Not estimates. Each row below was produced by running the file through this page in a real browser and measuring the result, at the default quality of 82.
| Test image | PNG in | BMP out | Change |
|---|---|---|---|
| Smooth gradient 1600 × 1200, broad tonal transitions — where banding and blocking show | 1.8 MB | 7.3 MB | +318% |
| UI screenshot 1440 × 900, dense text on flat panels — the hardest case for JPEG | 97 KB | 4.9 MB | +5100% |
| Line-art diagram 1200 × 800, hard edges and large flat areas | 19 KB | 3.7 MB | +19433% |
| Logo with transparency 512 × 512, flat colour on a transparent background | 77 KB | 1.0 MB | +1230% |
Every test image got larger. That is expected for this pair rather than a fault: BMP is not the efficient choice for content that already suits PNG, and you are converting for compatibility or for editing headroom, not to save space. Measured in Chrome 150.0.7871.46; other browsers encode slightly differently.
What to watch out for
- Massive files — often 10× a JPEG of the same image
- No animation, and inconsistent transparency support across variants
- Impractical for the web or for sharing
About the two formats
PNG stores every pixel exactly as it was, with no generation loss no matter how many times you re-save it. That fidelity is why it dominates screenshots, logos and UI assets, and also why it is the wrong choice for photographs — lossless compression simply cannot get a 12-megapixel photo down to a reasonable size.
BMP stores pixels essentially uncompressed, which makes it enormous — a 12-megapixel photo lands around 36 MB, roughly 11× the same image as a JPEG. It persists mainly inside legacy Windows software, scanning utilities and embedded systems where decoding simplicity beats file size.
Other conversions
Everything runs on your device — nothing is uploaded, so there is no size limit, no queue and no copy left on a server afterwards. There is more on how browser-based conversion works if you want the detail. Otherwise, browse every image tool, or convert BMP back to PNG.