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Runs in your browser · nothing is uploaded

Convert BMP to PNG

BMP in, PNG out, in a second or two — processed on your device, nothing uploaded.

Processed on your device · nothing uploaded

Output format

What this tool does

It decodes your BMP file and re-encodes the pixels as PNG, losslessly. The file is read, converted and offered back as a download without touching the network.

About BMP

BMP is the uncompressed Windows bitmap: the raw pixels with a small header. It dates from Windows 1.0 and is still what MS Paint, many scanners and some industrial or embedded tools produce by default. It is good for legacy software, embedded devices and a few specialist tools that require it; less good for almost everything else — it is huge (a 1920×1080 screen capture is 6 MB), carries no useful metadata and browsers won't show it inline on web pages. Opens on Windows and most desktop editors; web browsers can display it but websites never serve it.

About PNG

PNG is the lossless raster format of the web: every pixel is stored exactly, with an optional alpha channel for transparency. It was designed in 1996 as a patent-free replacement for GIF and is supported by literally everything that shows images. It is good for screenshots, logos, icons, UI graphics, anything with sharp edges, flat colour or text, and anything that needs a transparent background; less good for photographs — a photo saved as PNG is typically 5–10× larger than the same photo as a good-quality JPEG with no visible benefit. Universal: every browser, OS, editor, office suite and messaging app since the late 1990s.

What changes going from BMP to PNG

  • Quality: nothing is lost — PNG stores the decoded pixels exactly.
  • Size: Exactly width × height × 3 bytes plus a header, no matter what the picture shows vs. small for flat graphics, very large for photos (a 12-megapixel photo is 20–30 MB as PNG).
  • Metadata: EXIF (camera, date, GPS) is not carried over — the browser decodes pixels, not tags. That is a privacy plus for sharing and a minus if you rely on dates in the file.

Lossless and 5–20× smaller

PNG stores the identical pixels with real compression, so a BMP becomes a PNG with no change in appearance and a fraction of the size. This is the right conversion for screenshots, scanned text and graphics; for photographs, JPEG would be smaller still.

How to convert BMP to PNG

  1. Drop the BMP file on the panel above or click to choose it.
  2. PNG is pre-selected. Press Convert to PNG.
  3. Download. The file is named after the original with a .png extension.

Frequently asked questions

Is my BMP file uploaded?

No. The page is static and has no upload endpoint; your browser does the work on your own device and the result is saved straight back to your disk. The site's Content-Security-Policy only allows it to talk to its own origin, so it cannot send your file anywhere even by accident. Load the page, disconnect from the internet, and it still works.

Does BMP to PNG lose quality?

No. PNG is lossless: the pixels the browser decoded from your BMP are stored exactly.

Will transparency survive?

BMP has no transparency to begin with, so there is nothing to lose; the PNG output is fully opaque, exactly like the source.

Is it free? Any limits or watermark?

Free, no account, no watermark, no daily quota. Because nothing runs on our servers there is nothing to meter. The only limits are your device's memory — anything up to roughly 50 megapixels is fine on a modern phone or laptop.

Can I do several files at once?

One file at a time at the moment — drop the next one as soon as you have downloaded the first. Batch processing with a ZIP in and out is planned.

Does it work on my phone?

Yes — iPhone, iPad and Android browsers all run it. Large files take a few seconds longer on a phone than on a laptop.