Makes a proper Windows icon from a PNG. An .ico is a container holding several resolutions at once, and this writes all of them into one file — not a single image with the extension changed.
Why an icon holds several sizes
Given only one size the system scales it, and scaling a 256-pixel image down to 16 turns fine detail into mush — which is why a favicon made from a detailed logo so often looks like a smudge in the tab.
Each size here is rendered separately from the source at full quality rather than downscaled from a larger rendering, which is the best a converter can do. For a genuinely good 16-pixel icon you want a simplified design drawn for that size — no automatic process substitutes for that.
Transparency and the PNG-inside-ICO trick
The older approach — a BMP inside the icon with a separate 1-bit mask — gives hard, jagged edges wherever the icon is not fully opaque. PNG entries avoid that entirely.
Using it as a favicon
favicon.ico at the root of your site. Browsers request it there automatically even with no markup, which is exactly why the .ico format persists.
To be explicit, and to add a modern SVG alongside it:
<link rel="icon" href="/favicon.ico" sizes="any">
<link rel="icon" href="/icon.svg" type="image/svg+xml">
Start from a square source. A non-square image is squashed to fit, and the tool tells you when that happens.
Other names for this
Also searched as “png to favicon”, “make favicon from png”, “png to icon”.
Questions
- Which sizes do I need?
- 16, 32 and 48 covers browsers, the taskbar and file listings. Add 256 if the icon is for a desktop shortcut.
- Is transparency kept?
- Yes. Each entry is a PNG inside the container, which keeps the full alpha channel with clean edges.
- My source is not square.
- It is squashed to fit, and you are told. Crop it square first for a good result.
- Do I still need a favicon.ico?
- It is still the most compatible option, and browsers request it from the site root without any markup. Pair it with an SVG icon for modern browsers.
- Can I convert a whole folder of images?
- Yes. Drop as many files as you like, or a whole folder. Each keeps its original name with the new extension —
IMG_4032.heicbecomesIMG_4032.jpg, neverconverted_1.jpg— and you can download them individually or as a ZIP. - Are my photos uploaded?
- No. The decoding and re-encoding happen in this tab using the browser’s own image support. Photos are personal in a way most files are not, and none of them is transmitted. Turn your Wi-Fi off and the converter keeps working.