Simple logo mark
- Input
- 512 × 512 PNG of a single letter
- Output
- Multi-size .ico, clear at every size
Simple, high-contrast shapes survive being scaled to 16 pixels. That is the whole trick to a good favicon.
ICO Generator
An ICO file is the format browsers expect for a favicon, and it can hold several sizes in one file so the browser picks the right one. Upload a square image and this generator produces a multi-size .ico containing 16, 32, 48 and 64 pixel versions, ready to drop at your site root.
Runs entirely in your browser — your images are never uploaded.
How to
How to use the ICO Generator
- 1
Upload a square image
A PNG with transparency works best. Non-square images are padded rather than stretched.
- 2
Check the sizes
Previews show how it looks at each size — a detailed logo often becomes unreadable at 16 pixels.
- 3
Generate
All sizes are packed into a single .ico file.
- 4
Add it to your site
Place favicon.ico at your site root. Browsers find it automatically.
Examples
ICO Generator examples
Detailed logo
- Input
- Full wordmark with fine text
- Output
- Unreadable smudge at 16 pixels
The preview shows this before you publish. Use a simplified mark for the favicon and keep the wordmark elsewhere.
Transparent background
- Input
- PNG with alpha
- Output
- ICO keeps the transparency
ICO supports transparency, so the favicon sits cleanly on light and dark browser chrome alike.
Why use it
What the ICO Generator gives you
One file, every size
Browsers and operating systems request different sizes. A multi-size ICO satisfies all of them without extra files.
See it at 16 pixels first
The preview shows the smallest size honestly, which is where most logos fall apart.
Transparency kept
The alpha channel survives, so the icon works against any browser theme.
Non-square handled properly
A rectangular image is padded to square rather than squashed, which is what most generators do to it.
Runs locally
Your logo is never uploaded.
Good to know
ICO Generator limitations
- Favicons are tiny. Detailed logos and text will not be legible at 16 or 32 pixels regardless of the source quality.
- Modern sites often also want PNG icons and an apple-touch-icon; ICO alone covers browsers but not every platform.
- Very large source images are downscaled before packing, which is normal for this format.
- Images are limited to 25 MB.
Summary
ICO Generator in short
- An ICO file holds several icon sizes in one file, which is why browsers prefer it for favicons.
- Place favicon.ico at your site root and browsers find it without any HTML.
- Simple high-contrast marks work; detailed logos and text do not survive 16 pixels.
- ICO supports transparency, so the icon suits light and dark browser chrome.
FAQ
ICO Generator questions
What is an ICO file?
A Windows icon format that can store several images at different sizes in a single file. Browsers use it for favicons because one file then serves every context that needs a different size.
Which sizes do I need?
16 and 32 pixels cover browser tabs and bookmarks, 48 covers Windows shortcuts, and 64 covers higher-density displays. This generator includes all four.
Where does the file go?
At the root of your site, as favicon.ico. Browsers request that path automatically, so no HTML is strictly required — though a <link rel="icon"> tag makes it explicit.
What makes a good favicon?
One simple shape, strong contrast and no fine detail. At 16 pixels you have roughly 256 pixels in total, so a single letter or symbol reads and a full wordmark does not.
Can I just use a PNG?
Modern browsers accept PNG favicons, and many sites use both. ICO remains the most broadly compatible single file, particularly for older browsers and Windows shortcuts.
Why is my new favicon not appearing?
Browsers cache favicons aggressively, sometimes for weeks. Hard-refresh, try a private window, or append a query string to the link tag to force a re-fetch.
Does ICO support transparency?
Yes. Keeping the background transparent is recommended so the icon looks right against both light and dark browser themes.
What if my image is not square?
It is padded to a square rather than stretched, so proportions are preserved. For best results, supply a square image with the mark already centred.
Does making a favicon involve a server?
No. Your logo is drawn to a canvas at each size and the .ico file is assembled byte by byte in your browser. Nothing is transmitted, so an unreleased brand mark stays private.
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