How to use the png to ico converter
- Choose a PNG, or another image such as JPG, WebP or SVG, or drop it on the box. A square image of at least 256 pixels works best.
- Tick the sizes to include. The defaults are 16, 32, 48 and 256 pixels. Favicons usually need 16, 32 and 48.
- If the picture is not square, choose whether to fit it inside with transparent padding or fill the square and crop the edges.
- Check the previews, then press Create and download .ico.
- The page opens the new file again and lists what is inside it, so you can see each size, its format and its byte count.
What an ICO file is
An ICO file is a container that holds several versions of one icon at different sizes, so Windows or a browser can pick the sharpest one for each place it appears: a 16 pixel tab, a 32 pixel taskbar button, a 48 pixel desktop icon or a 256 pixel large view. The file starts with a six byte header, then a 16 byte directory entry for each image giving its width, height, color depth, length and position, followed by the image data.
This tool stores each size as a PNG inside the container. That format is supported by Windows Vista and later and by current browsers, and it keeps full transparency and smooth edges. A size of 256 is written in the directory as zero, as the format requires. Very old software from the Windows XP era may not read PNG-compressed icons.
Getting a sharp result
Start from the largest, cleanest image you have, ideally a square PNG of 512 pixels or more. Each size is drawn from the original in gentle steps, and the smallest sizes are the hardest to keep readable, so simple shapes with thick lines survive better than fine detail. Check the 16 pixel preview especially.
A picture that is not square would be distorted if it were squeezed into a square, so the tool never stretches it. Fit leaves transparent bands, and fill crops the longer side evenly from both ends.
Using the icon, and privacy
For a website, save the file as favicon.ico in the root folder of the site, or reference it with a link tag in the page head. For a Windows shortcut, choose the file in the shortcut properties. Your image is read and converted in this browser tab, is never uploaded, and the output is built in memory then downloaded. The limit is 25 MB for the source image.
Assumptions and limits
- Output images are PNG-compressed, 32 bits per pixel with transparency.
- Sizes available are 16, 24, 32, 48, 64, 128 and 256 pixels, all square.
- Source files up to 25 MB are accepted. Animated images use their first frame, and SVG is drawn at 512 pixels first.
- HEIC photos are not supported. Convert them to JPG or PNG first.
- Very old software may not open ICO files with PNG data.
Frequently asked questions
How do I convert a PNG to an ICO file?
Choose your PNG, keep the sizes you need ticked, and press Create and download. The page builds the ICO in your browser and gives you the file straight away without uploading anything.
Which icon sizes should I include in a favicon?
Sizes of 16, 32 and 48 pixels cover browser tabs and bookmarks on most devices. Add 256 if the same file will serve as a Windows application icon, since that is the largest size Windows shows.
Does the ICO keep transparency?
Yes. Each size is stored as a PNG with an alpha channel, so transparent areas of your PNG stay transparent. JPG sources have no transparency to keep.
Why does the tool not accept my HEIC photo?
Browsers cannot reliably decode HEIC, so it is not supported. Export the photo as JPG or PNG from your photo app and use that file instead.
Can I check what is inside the ICO afterward?
The page does it for you. After building, it reads the new file back and lists every size, whether it is PNG, and its byte count. Need a different size or format? Try the image converter or the image resizer.