twineconvert

free · in-browser · no upload

ICO to BMP
Converter

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

or drop your file

Select your file here to get started

or drop your file here.

Accepts .ico

nothing uploaded no file size cap no signup

How it works

Three steps. No upload, no signup.

  1. 1

    Drop your file

    Click the dropzone above or drag a ICO 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 BMP 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. Drop a file, get a converted file.

Why convert ICO → BMP

What this conversion is actually for

BMP is the uncompressed bitmap Windows utilities, some scanners, and older software still expect. This converts ICO images to BMP entirely in your browser, so the file never leaves your device. Output is a standard 24-bit uncompressed bitmap.

A real example

You have a ICO image and need BMP for a site, app, or workflow that requires it. Drop the ICO here and download the BMP, no upload.

Troubleshooting

The BMP is large.

BMP is uncompressed by design and much bigger than the source; PNG (lossless, compressed) is usually a better target if size matters.

Formats involved

About ICO and BMP

ICO, Icon

ICO is Microsoft's icon format, a single file containing the same icon at multiple sizes (typically 16, 32, 48, 64, 128, 256 pixels). Browsers use the favicon at the top of every tab. Modern websites can use PNG favicons too, but ICO remains the universally-supported choice especially for older browsers and Windows desktop integration.

How to open

Browsers and Windows recognize ICO natively. macOS treats them as standard images. Modern image editors read multi-resolution ICOs; some older tools only see the first size.

Full ICO format guide →
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 →

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FAQ

Common questions

Is this ICO → BMP converter really free?

Yes. No signup, no watermark, no daily file count limit. Every conversion runs in your browser, your file never touches our servers because there are no servers.

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 ICO to BMP?

Browser favicons and Windows desktop icons. Legacy Windows software, hardware drivers, certain industrial applications. The most common reason to convert is compatibility, BMP works in places where ICO doesn't, or vice versa.

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

Browsers and Windows recognize ICO natively. macOS treats them as standard images. Modern image editors read multi-resolution ICOs; some older tools only see the first size.

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.