BMP Won't Open? Convert to ICO Instantly
Fast, instant BMP to ICO conversion. No signup required. Just drop your .bmp file and get .ico in seconds.
Batch Settings
デジタルの世界では、画像ファイル形式の選択一つで、その印象や使い勝手が大きく変わることがあります。特に、ウェブサイトのファビコンやアプリケーションのアイコンなど、限られた小さなスペースでブランドやコンテンツを表現する場合、画質の維持とファイルサイズの最適化は非常に重要です。BMP形式は高画質ですが、そのままではアイコンとして使いにくい場面も少なくありません。そこで、本ページでは、BMP画像をWindows標準のアイコン形式であるICOへ変換するプロセスを、日本のユーザーの皆様に分かりやすくご紹介します。この変換によって、あなたの画像がより多くのデバイスやプラットフォームで、美しく、そして効率的に表示されるようになります。あなたの創造性を、より幅広いデジタル環境で輝かせましょう。
- ウェブサイトのファビコン作成
- デスクトップショートカットアイコン
- ビジネス向けアプリのアイコン
日本のデザインでは、細部の表現やフォントの美しさが重視されるため、ICO変換時にも元のBMPの品質が損なわれないよう、特に注意を払うことが推奨されます。特に縦書きテキストを含む場合、視認性の維持が重要です。
About BMP to ICO Conversion
Dealing with a BMP file that won't open on your device? You're not alone — BMP compatibility issues are one of the most common reasons people search for a file converter. BMP is an uncompressed raster format that preserves every pixel but produces very large files.
The fix is simple: convert your BMP to ICO. ICO is the icon format used for website favicons and Windows application icons. This conversion lets you convert between formats quickly, solving the problem in seconds rather than hours of troubleshooting.
Full Name: BMP uses Bitmap Image, while ICO uses Icon File. Compression: BMP uses None (uncompressed), while ICO uses Lossless. Transparency: BMP uses No, while ICO uses Yes. Converting BMP to ICO maintains high quality with CocoConvert's optimised encoder settings.
CocoConvert processes your BMP file on secure servers in Germany — upload, convert, download. Your files are encrypted via TLS and automatically deleted within 24 hours. No account needed, no software to install, and it works on any device with a browser.
This conversion is ideal when you You need a file that works in web browsers, or when you You need maximum device and software compatibility.
The conversion engine behind CocoConvert uses FFmpeg, Sharp, and qpdf — the same open-source libraries trusted by Netflix, YouTube, and enterprise platforms. Pro users can batch convert up to 100 files at once.
How to Convert BMP to ICO
- 1
Add your BMP file
Drag and drop your .bmp file into the converter, or tap "Browse" to pick it from your device. Multiple files are supported for batch processing.
- 2
Pick ICO output
Select .ico as the target format. CocoConvert automatically applies the best quality settings for this conversion.
- 3
Start conversion
Hit the Convert button. The image engine processes your file server-side — no CPU drain on your device.
- 4
Save your file
Once done, download your .ico file. For batch jobs, download all at once as a zip.
What Happens When You Convert BMP to ICO
Your BMP image is decoded into raw pixel data, then re-encoded as ICO. No quality loss — pixel data is preserved exactly.
Your BMP file is decoded — the compressed/stored pixel data is expanded into raw RGB pixels
Pixels are re-encoded using Icon File's lossless compression
Metadata (EXIF, ICC profiles) is transferred where ICO supports it
The ICO file is saved and ready for download
BMP vs ICO — Detailed Comparison
| Feature | .BMP | .ICO |
|---|---|---|
| Full Name | Bitmap Image | Icon File |
| Compression | None (uncompressed) | Lossless |
| Transparency | No | Yes |
| Animation | No | No |
| Color Depth | up to 32 bits/channel | 32-bit (with alpha) |
| HDR Support | No | No |
| Typical File Size | 10–50 MB per photo (uncompressed) | <100 KB |
| Platform Support | Universal | Universal |
| Browser Support | Limited | Universal |
| Year Created | 1986 | 1985 |
| Open Standard | No | No |
Should You Convert BMP to ICO?
When to Convert
- ✓You need a file that works in web browsers
- ✓You need maximum device and software compatibility
Frequently Asked Questions
Why won't my BMP file open?
BMP files may not open if your device lacks the right codec or application. Converting to ICO — a more widely supported format — usually resolves this. ICO is the icon format used for website favicons and Windows application icons.
Is it safe to convert BMP to ICO online?
Yes. CocoConvert encrypts your file via TLS, processes it on isolated servers in Germany, and permanently deletes it within 24 hours. Your files are never shared or analysed.
Will I lose quality converting BMP to ICO?
Converting BMP to ICO maintains high quality with CocoConvert's optimised encoder settings. CocoConvert uses high-quality encoder defaults to preserve as much fidelity as possible.
How large can my BMP file be?
Free users can convert files up to 250 MB each. Pro users get a 5 GB limit per file, and Business API users have custom limits.
Can I convert BMP to ICO on my phone?
Absolutely. CocoConvert works in any modern browser — iOS Safari, Android Chrome, and all desktop browsers. No app required.
Versions are pinned in our worker Dockerfile and re-built via CI on every change.