Convert PNG to ICO for a crisp favicon
A favicon is the tiny image that gives a website its visual signature. You see it in the browser tab next to the page title, in your bookmarks list, in the address bar drop-down of your browsing history, and sometimes alongside search results. It is small, but it does a lot of work: a recognisable favicon helps users find your tab among a dozen others and signals that a site is finished and cared for. The classic format for that little icon is ICO, and the easiest way to make one is to start from a clean square PNG and convert it.
This tool takes a PNG image and turns it into an ICO favicon right inside your browser. The conversion runs locally using your own device, so the picture you pick is never uploaded to a server. That matters when your icon is a logo or brand asset you would rather not hand to a third party. When the file is ready, you simply download it.
What the ICO format is and why it holds several sizes
ICO is an icon container format that originated in Microsoft Windows, where it stores the icons used for programs, shortcuts and folders. Its defining feature, and the reason it became the standard for web favicons, is that a single ICO file can hold the same image at several resolutions at once. Instead of one fixed bitmap, the file packs a small set of square images and lets the browser or operating system pick whichever size fits the place it needs to draw the icon.
That is genuinely useful. A browser tab needs a tiny icon, a bookmark bar might use a slightly larger one, and a pinned shortcut on the desktop can ask for something bigger still. With a multi-size ICO, each context grabs the version that suits it, so your icon stays sharp rather than being scaled up from a single small bitmap and turning blurry. ICO also preserves transparency, which keeps the corners of a round or irregular logo clean against any tab colour.
Recommended favicon sizes
For a website favicon, the three sizes worth including are 16x16, 32x32 and 48x48 pixels. The 16-pixel version is the one most browsers show in the tab and address bar. The 32-pixel version is used on higher-resolution displays and in some bookmark and history views, so it keeps things crisp on modern screens. The 48-pixel version covers larger contexts such as Windows site shortcuts. Because they all live inside one ICO file, you ship a single asset and let each surface choose what it needs.
Start from a square PNG so nothing gets stretched. If your source image is rectangular or oversized, crop or scale it to a clean square first with our image resizer, then run the conversion. A simple, high-contrast design reads far better at 16 pixels than a detailed illustration, so favour bold shapes over fine text.
How to add the favicon to your site
Once you have your ICO file, upload it to your website, traditionally to the site root as favicon.ico. Many browsers will find it there automatically, but it is best practice to declare it explicitly in the head of your HTML so there is no guesswork. Add a link tag like this:
<link rel="icon" type="image/x-icon" href="/favicon.ico">
Place that line inside the <head> section of your pages. The rel="icon" attribute tells the browser this resource is the page icon, and the href points to wherever you stored the file. If you use a root-relative path like the one above, the same declaration works across every page of your site. After deploying, you may need to do a hard refresh or clear the cache before the new icon appears, since browsers hold on to favicons aggressively.
Private conversion in your browser
Everything happens on your device. The PNG you choose is read, decoded and re-encoded as an ICO locally, and nothing leaves your machine during the process. There is no account, no queue and no server-side storage, which makes this convenient even for unreleased logos or client work under an agreement. For more ways to prepare and tidy up graphics, browse our full set of image tools.
Frequently asked questions
Is my image uploaded anywhere?
No. The PNG is converted to ICO entirely in your browser on your own device. Nothing is sent to a server and nothing is stored, so your image stays private.
What sizes should my favicon include?
The most useful sizes are 16x16, 32x32 and 48x48 pixels. The 16-pixel image is shown in browser tabs, while the larger ones keep the icon sharp on high-resolution displays and desktop shortcuts.
Why use ICO instead of just a PNG?
ICO is the long-standing favicon format and it can store several sizes inside one file. Browsers and the operating system pick the resolution that fits each context, so the icon stays crisp instead of being scaled from a single bitmap.
Does the ICO keep transparency from my PNG?
Yes. The ICO format supports transparency, so the see-through areas of your PNG are preserved and the icon blends cleanly with any tab or background colour.
How do I add the favicon to my website?
Upload the ICO file to your site, usually as favicon.ico in the root, and add a link tag in the head of your HTML such as link rel icon type image x-icon href slash favicon.ico. Then clear your browser cache to see it.
My source image is not square. What should I do?
Crop or scale it to a square first so it is not stretched. You can use our image resizer to make a clean square, then convert that to ICO for the best looking favicon.