01
Image Compressor
Compresses images to a target quality or file size in your browser, with a live…
Image to ICO Converter
Packs one image into a real multi-size .ico file with 16, 32, 48 and larger icons inside, built entirely in your browser.
Image
Nothing uploaded
No sign-up
Free, unlimited
Drop a square imageat least 256 px for the larger sizes — nothing is uploaded
Add a file to begin.
In short
Image to ICO Converter is a free online tool on inputtesthub.com that packs one image into a real multi-size .ico file with 16, 32, 48 and larger icons inside, built entirely in your browser. It needs no account, no download and no payment, and there is no daily usage limit. Everything is processed inside your own browser, so the data you paste is never uploaded to a server.
How to use the Image to ICO Converter
- Drop in a square image, ideally 256 px or larger.
- Tick the sizes you need — 16, 32 and 48 are what Windows asks for.
- Choose a background if the source has transparency you do not want.
- Build the .ico and download it.
About the Image to ICO Converter
The Image to ICO Converter packs one image into a real multi-size .ico file with 16, 32, 48 and larger icons inside, built entirely in your browser. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Making a favicon.ico that Windows and older browsers can both use.
- Producing a desktop shortcut icon from a logo.
- Building an application icon without installing an icon editor.
Details
| Container | ICONDIR header, one 16-byte entry per size, then the images |
|---|---|
| Encoding | PNG inside ICO — the form Windows has accepted since Vista |
| 256 px | Written as 0 in the size byte, because 256 does not fit in one byte |
| Colour depth | 32-bit with an alpha channel |
| Windows XP | Cannot read PNG-in-ICO; it needs the older BMP form |
The Favicon Generator on this site produces the PNG set and the HTML that modern browsers prefer. This is the companion for the one file they do not cover — a genuine multi-image .ico, which is still what Windows uses for shortcuts, taskbar entries and file associations.
Where this tool stops
Writes the PNG-in-ICO form only, so Windows XP cannot read the result. Cursors (.cur), which share the container format, are not produced.
Frequently asked questions
Can I not just rename a PNG to favicon.ico?
Browsers will usually accept it, and Windows will not. A real ICO is a small archive holding several images at different sizes, and the operating system picks the one that fits the place it is drawing — a 16 px taskbar entry, a 48 px list, a 256 px thumbnail. A renamed PNG gives it one image and nothing to choose from, so everything is resampled from the same source.
Which sizes do I actually need?
16, 32 and 48 cover Windows. Add 256 if the icon will ever appear as a large thumbnail, because Windows scales that view from the largest entry it can find. Every extra size adds a few kilobytes, so there is little reason to include all seven.
Why does my icon look blurry at 256 px?
Because the source was smaller than 256 and had to be scaled up. Icons show that instantly — they are viewed at exact pixel sizes with no surrounding detail to distract the eye. Start from a vector or a large PNG, and untick sizes larger than your source.
Is the Image to ICO Converter free?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Does anything I enter leave my computer?
No. The Image to ICO Converter runs entirely in your browser using JavaScript. Your input never reaches inputtesthub.com or any third party — open your browser's Network tab while you use it and you will see no request go out.
What do people use the Image to ICO Converter for most?
The jobs it is built for: making a favicon.ico that Windows and older browsers can both use. Producing a desktop shortcut icon from a logo. Building an application icon without installing an icon editor. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
What are the limits of the Image to ICO Converter?
Writes the PNG-in-ICO form only, so Windows XP cannot read the result. Cursors (.cur), which share the container format, are not produced. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What are the reference figures here?
Container is ICONDIR header, one 16-byte entry per size, then the images. Encoding is PNG inside ICO — the form Windows has accepted since Vista. 256 px is Written as 0 in the size byte, because 256 does not fit in one byte. These are printed on the page itself, so you do not have to take them on trust.
How large a file can I use?
There is no limit set by us, because your file is never uploaded — the only ceiling is the memory your own browser will give the tab. Very large files simply take longer to process, and a phone will give up sooner than a desktop.
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