twineconvert
Free · in-browser · no upload

BMP to PNG
Converter

Drop your BMP file. We'll convert it to PNG right here in your browser, your file never leaves your device.

Local

Drop your file here

or click to pick from your device

.bmp
Nothing uploaded No file size cap Open source

How it works

Three steps. No upload, no signup.

  1. 1

    Drop your file

    Click the dropzone above or drag a BMP from your desktop. Files of any size, there's no upload, so there's no upload limit.

  2. 2

    Convert in your browser

    The conversion runs entirely in this tab using JavaScript and WebAssembly. Your file never touches our servers, we don't have any.

  3. 3

    Download

    Get your PNG the moment the conversion finishes. Convert another, or close the tab.

Files stay on your device

Your file is never uploaded. The entire conversion runs in your browser using WebAssembly. We can't see what you convert because we have no server to see it.

No file size limit

Server converters cap free users at 1-2 GB and gate larger files behind a paid plan. Since nothing uploads, our limit is whatever your browser can handle.

Free, no signup, no ads on conversions

No account required. No watermark on the output. No queue. Open source, every line of conversion code is public.

Formats involved

About BMP and PNG

BMP, Bitmap Image File

BMP is Microsoft's original bitmap format from the late 1980s. It stores raw pixel data with minimal compression, which makes BMP files enormous (a 1080p screenshot is about 6 MB as BMP, 200 KB as PNG). The format remains common in Windows-internal contexts (clipboard, certain printer drivers, older industrial software) but is rarely chosen as a delivery format today.

How to open

Universal, every OS, browser, and image editor reads BMP. The format is so old it predates compatibility concerns.

Full BMP format guide →
PNG, Portable Network Graphics

PNG is a lossless image format, the file size is larger than JPG, but every pixel is preserved exactly. It supports full transparency (alpha channel), which JPG cannot. Created in 1996 specifically as a patent-free replacement for GIF, PNG is the standard for screenshots, logos, icons, UI graphics, and any image that needs sharp text or transparent backgrounds.

How to open

Universal support, every OS, browser, and image editor reads PNG. macOS Preview, Windows Photos, and any web browser open PNGs without any conversion step.

Full PNG format guide →

Related tools

Convert other files to PNG

Convert your BMP to other formats

How we compare

BMP → PNG vs the alternatives

FeatureUstwineconvertCloudConvertiLovePDFFreeConvertSmallpdf
Files uploaded to a server
Free file size limitNo limit1 GB200 MB1 GB5 GB
Free conversions per dayUnlimited10/dayLimitedLimited2/day
Signup required
Watermark on output
Open source
Works offline (after first load)

Last verified May 2026 from each competitor's pricing and FAQ pages. Limits and pricing change frequently.

FAQ

Common questions

Is this BMP → PNG converter really free?

Yes. No signup, no watermark, no daily file count limit. The entire engine is open source, you can read the conversion code on GitHub.

Where does my file go when I convert it?

Nowhere. The conversion runs entirely in your browser using JavaScript and WebAssembly. Your file is never uploaded to our servers. We don't have any servers handling files, there's nothing for us to log, store, or accidentally leak.

What's the maximum file size?

Whatever your browser can hold in memory. Practically, this means a few hundred MB on most computers, significantly larger than the 1-2 GB caps that server-upload converters charge for. Very large files (multi-GB) may require closing other browser tabs first.

Why convert BMP to PNG?

Legacy Windows software, hardware drivers, certain industrial applications. Screenshots, logos, UI graphics, and any image needing transparency. The most common reason to convert is compatibility, PNG works in places where BMP doesn't, or vice versa.

How do I open a BMP file in the first place?

Universal, every OS, browser, and image editor reads BMP. The format is so old it predates compatibility concerns.

Does this work offline?

Once the page is loaded, the conversion itself runs entirely offline. The first time you use a tool, your browser downloads the conversion library (a one-time cache). If you reload while offline, the page won't load, but you can install the site as a Progressive Web App for full offline use.

Can I convert multiple files at once?

Single file at a time for now. Batch conversion is on the roadmap, for now, drop one file, download the result, then convert the next.