PNG to BMP Online
Convert PNG (or JPG, WebP, GIF) to a 32-bit Windows BMP with alpha preserved. Lossless, browser-only, no upload.
Drop a PNG to convert to BMP
32-bit Windows BMP with alpha — stays on your device
How to convert PNG to BMP online
Drop a PNG (or any image format your browser can decode — JPG, WebP, GIF, AVIF, HEIC, even an existing BMP) onto the upload area. ToolChop renders it to a canvas, reads the pixel data, and assembles a 32-bit Windows BMP file: a 14-byte BITMAPFILEHEADER + 40-byte BITMAPINFOHEADER, BI_RGB compression (uncompressed), 32 bits per pixel, BGRA layout, bottom-up rows. The file is byte-for-byte standards-compliant and opens in every BMP viewer.
Why a local PNG-to-BMP converter matters
The reasons people convert to BMP are usually legacy or embedded: an old Windows application, a scanner driver, an industrial controller, a microcontroller display driver that needs raw pixel data. These workflows already deal with internal or sensitive material. Uploading the source PNG to a third-party converter site adds an unnecessary data path. ToolChop converts entirely in your browser, so the image and the resulting BMP never leave your device.
Why is the BMP so much bigger than the PNG?
PNG uses lossless compression; BMP does not. A 1 MB PNG typically expands to 5–10 MB as a 32-bit BMP because every pixel takes 4 raw bytes with no compression. That is the BMP format's nature — and the whole reason it is still used in legacy and embedded contexts where decompression code is too heavy to include.
What you can do
- Convert PNG, JPG, WebP, GIF (first frame), BMP, AVIF, or HEIC to BMP
- 32-bit output preserves the alpha channel exactly
- Byte-for-byte color fidelity — no quantization or profile conversion
- Standards-compliant Windows BMP that Paint, Photoshop, GIMP, and embedded toolchains all accept
- Browser-only — image and result never uploaded
Frequently asked questions
How do I convert a PNG to BMP online for free?
Drop your PNG onto the upload area. ToolChop renders it to a canvas in your browser, reads the pixel data, and writes a standard 32-bit Windows BMP file. Click Download .bmp. No account, no upload, no daily limit.
Does ToolChop upload my PNG?
No. Conversion runs entirely in your browser using the Canvas API and a hand-rolled BMP encoder. The image and the resulting BMP never leave your device — useful when your PNG is a screenshot of an internal dashboard, a branded asset, or anything you do not want a third-party server to see.
What BMP variant does ToolChop produce?
A standard 32-bit Windows BMP using BITMAPINFOHEADER, BI_RGB (uncompressed), and BGRA pixel layout in bottom-up row order. This is the most compatible BMP format — readable by Windows Paint, Photoshop, GIMP, IrfanView, and every modern image library.
Does the BMP preserve PNG transparency?
Yes. 32-bit BMP stores an alpha channel per pixel, so transparent PNG areas come through as transparent BMP pixels. Some older BMP viewers ignore the alpha channel and display transparent areas as black — that is a limitation of those viewers, not the file.
Why is the BMP file so much larger than the PNG?
BMP is uncompressed. PNG uses lossless DEFLATE compression, which typically shrinks photographs and screenshots by 5–10× compared to raw pixel data. A 1 MB PNG can produce a 5–10 MB BMP — that is the format's nature, not a bug.
Why would I want a BMP if PNG is smaller?
Three common reasons. (1) Legacy software: many older Windows applications, scanner drivers, and industrial controllers only read BMP. (2) Embedded systems: BMP is trivial to parse on tiny microcontrollers — no decompression code required. (3) GIS / CAD interoperability: some specialized formats expect raw BMP input.
Will the colors match exactly?
Yes, byte-for-byte. The pixel values in the BMP are the same RGB values your browser decoded from the PNG. There is no color-profile conversion, no quantization, and no lossy step. What you see in the source is what is in the BMP.
Can I convert JPG, WebP, or GIF to BMP too?
Yes. The upload accepts any image format your browser can decode — JPG, PNG, WebP, GIF (first frame), BMP (re-encoded), AVIF (modern Chrome), HEIC (Safari). The output is always a 32-bit Windows BMP.
Is there a file size or resolution limit?
Only your browser's memory. A 4K (3840×2160) image produces a roughly 33 MB BMP, which works fine in modern Chrome. Beyond ~8K (8000×8000) some browsers throttle Canvas operations; if you hit that, downsize the PNG first using our Image Resizer.
Why does Windows Paint open my BMP as 24-bit?
Windows Paint sometimes silently drops alpha when re-saving a 32-bit BMP. The file ToolChop produces is genuinely 32-bit — verify in IrfanView or a hex editor (look at the biBitCount field at offset 28 of the header — it will read 32). Paint's display is just a viewer limitation.
Is the output a valid Windows BMP per the official spec?
Yes. The file uses the standard 14-byte BITMAPFILEHEADER followed by a 40-byte BITMAPINFOHEADER, with BI_RGB compression (value 0) and 32 bits per pixel. This is what almost every BMP-producing tool emits, and what every BMP-consuming tool expects.
Why use ToolChop instead of an online converter that uploads my image?
Privacy and predictability. PNGs are often screenshots, internal mockups, customer logos, or pre-publication assets you should not casually share. ToolChop converts entirely in your browser so the image never leaves your device, and the BMP is a deterministic, standards-compliant file with no watermark or signup wall.