Favicon checker

A small icon that has to look right everywhere

A favicon is the tiny image that appears in the browser tab, in bookmarks, in history and in search results on mobile. It is only 16 to 48 pixels wide on screen, yet it is one of the first things people associate with your brand. Because it is so small, details that look fine on a large logo turn into mush, and problems such as the wrong shape, a background that vanishes on dark tabs or a missing size are easy to overlook. This checker gives you a quick verdict on your file.

What it checks

• Format: PNG, SVG and ICO are supported by every modern browser. Formats like JPG or WebP work in most, but are not the usual choice.
• File size: a favicon is loaded on every visit, so it should be light, under 100 KB and usually much less.
• Shape: it should be square. A rectangular image is stretched or cropped by browsers.
• Resolution: browsers use 16 and 32 pixel icons, phones and shortcuts use 48, 180 and 192, and progressive web apps need 192 and 512.
• Transparency: a transparent background lets the icon sit on light and dark tabs. A solid background is fine if it is intentional.
• ICO contents: an .ico file can hold several sizes at once. The tool reads which ones are inside.

What a complete set looks like

A modern setup needs only a few files: an icon.svg that scales to any size, a favicon.ico with 32 pixel or 48 pixel images for older browsers, an apple-touch-icon.png of 180 by 180 pixels for iPhones and iPads, and a web app manifest with icons of 192 and 512 pixels for Android and installable apps. The tool shows a block of tags you can adapt, using the file names you choose.

Preview on light and dark

The same icon can look perfect on a white tab and disappear on a dark one. The preview shows the file at its real sizes on both backgrounds, so a black icon with transparency that vanishes in dark mode is easy to spot.

Limits

Browsers cannot read the files of another website, so this tool works on a file you upload, not on a web address. It only looks at the file on your device, which is never sent anywhere. For the design of the icon itself, remember that fine detail and text do not survive at 16 pixels, so a bold simple shape works best.