ICO to OTB Converter
Processing entirely on your device — large files may take a moment.
ICO is the Windows icon format. A single ICO file can bundle several sizes (16×16 up to 256×256) of the same icon, used for shortcuts, application icons and website favicons. Convert images to 1-bit OTB for retro phone displays.
iLoveConverter processes everything locally on your computer, which makes it private and fast: no upload wait, no server storage, no limits. Add as many files as you like — batch conversion is built in.
How to convert ICO to OTB
- 1
Select your files
Drag & drop your ICO files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to OTB". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted OTB file individually, or grab everything at once as a ZIP archive.
About the ICO format
ICO is the Windows icon container, and one of the oldest formats still in daily use. A single ICO file bundles several renderings of the same icon — 16×16, 32×32, 48×48 up to 256×256 — so Windows can pick the right sharpness for shortcuts, Explorer views and taskbars. Each member is stored as classic BMP data or, for large sizes, PNG compression.
On the web, favicon.ico at the site root remains the one icon request every browser makes automatically, which keeps the format alive despite cleaner alternatives like PNG and SVG icons. Keep ICOs small: every visitor downloads one.
+ Strengths
- ✓Multiple sizes bundled in one file
- ✓Every browser falls back to /favicon.ico automatically
- ✓Deep Windows integration for app icons
! Limitations
- −Practical size ceiling around 256×256
- −Windows-centric; little use outside icons
- −Quality is frozen at export time
About the OTB format
The Nokia OTA Bitmap coder of the ImageMagick set — the retro-phone format is written natively by the magick.wasm engine, entirely in your browser.
Obscure coder formats like this are exactly what template-driven converters list and never actually convert — here it really works.
+ Strengths
- ✓Written natively by ImageMagick
- ✓Runs entirely in your browser
- ✓Free, private, no watermarks
! Limitations
- −Niche format — few modern readers
- −Feature subset varies by coder
- −Keep the original for re-editing
Why convert ICO to OTB?
Think of it as moving your file to the container that fits the job. Practical size ceiling around 256×256 OTB works differently: Written natively by ImageMagick If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this ICO to OTB converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Will I lose quality converting ICO to OTB?
No — OTB is a lossless format, so every pixel of the converted image matches your original ICO file. You can also adjust the quality/size balance before converting when the target format supports compression.
Will transparent areas survive the conversion to OTB?
Transparency is kept whenever OTB actually supports an alpha channel. If the target format has none (like JPG), transparent areas are flattened onto a white background — that is a property of the format, not of this tool.
What happens to EXIF data and other metadata?
Conversions here re-encode the image, and re-encoding generally does not carry the original metadata over. If the EXIF data of your ICO files matters (camera model, GPS, timestamps), keep the original file as the master and treat the converted copy as the shareable version.