Choose one standard icon dimension, and the worker will resize the uploaded image into that square while preserving its aspect ratio. The output ICO contains the selected PNG-encoded subimage; it is not a multi-size icon bundle.
The converter is useful for quickly preparing a favicon-sized ICO from PNG, WebP, AVIF, JPG, GIF, or BMP inputs supported by the browser. Transparency can be preserved from alpha-capable inputs, but JPG sources remain opaque and the tool does not generate app icon manifests or server-side assets.
Common questions and answers about this topic.
No. All conversion runs entirely in your browser inside a Web Worker. Your images never leave your device.
For website favicons, 32×32 px is the standard browser-tab size, while 48×48 or 64×64 also covers bookmarks and shortcuts. This tool exports one selected size per ICO file; if you need a Windows desktop icon with multiple embedded sizes, generate the required sizes separately or use a dedicated icon packaging tool.
Yes. ICO files generated by this tool use 32-bit PNG-encoded subimages, fully preserving the alpha channel from PNG, WebP, or AVIF inputs. JPG inputs (which lack transparency) will produce an opaque icon — consider trimming the background first if you need transparency.
Yes. Add up to 20 images, and each one is converted to its own ICO file at the size you selected. When the batch finishes, download each file separately or press "Download completed" to get a single ZIP. The images are not merged into one multi-size icon.