About the PNG to ICO
Zyff's PNG-to-ICO converter takes one PNG and returns a single favicon.ico containing images at 16, 24, 32, 48, 64, 128 and 256 pixels. That is what ICO actually is — a container format holding several sizes in one file, not a single image with a different extension — and it is why a real .ico still beats a renamed PNG. This page opens with only the ICO selected, so you get the one file you came for rather than a zip of thirteen. Turn the other sections on if you want the full modern set as well. Conversion runs on Zyff's servers in memory only.
How to convert a PNG to ICO
Upload the PNG
A square PNG at 256px or larger gives every size in the file something real to downscale from. Transparency is preserved — ICO supports an alpha channel, which is the main reason it outlived the formats it competed with.
Pick the sizes inside the file
16, 32 and 48 cover browsers and Google's favicon selection. Adding 64, 128 and 256 costs a few kilobytes and covers desktop shortcut icons and high-DPI tabs.
Download favicon.ico
One file, holding every size you ticked. Each entry is a PNG payload, which every browser in current use reads.
Put it at your site root
Browsers request /favicon.ico from the root whether or not you declare it in HTML, so the root is where it does the most good with the least wiring.
What the PNG to ICO does
A real multi-size ICO
One file holding up to seven images. Renaming a PNG to .ico produces a file that some browsers accept and others reject, and no tooling can pick a size from.
Alpha preserved
ICO supports transparency, so a logo with a transparent background stays transparent instead of gaining a white box.
Nothing else generated
This page emits the .ico and stops. The manifest, apple-touch and Android sets are one switch away if you want them, and absent if you do not.
PNG payloads inside
Each entry is stored as PNG rather than a legacy BMP bitmap — smaller, and universally readable by current browsers.
Sized from one master
Every image in the file is downscaled from a single 1024px render, not from each other, so the 16px entry is as good as it can be.
At a glance
| Sizes available in the file | 16, 24, 32, 48, 64, 128, 256 px |
|---|---|
| Default selection | 16, 32, 48 px |
| Transparency | Preserved (ICO carries an alpha channel) |
| Encoding inside the container | PNG payload per entry |
| Accepted input | PNG, JPG, WebP, AVIF, SVG up to 25 MB |
| Output filename | favicon.ico |
Frequently asked questions
What is an .ico file, exactly?
A container that holds several images at different sizes in one file, each with its own colour depth and alpha channel. That is the difference from a PNG: a browser or an operating system asks the .ico for the size it wants and gets a purpose-made image rather than a downscale of a large one.
Do I still need favicon.ico in 2026?
It is no longer the primary icon, but it is still the one thing fetched without being asked for: browsers request /favicon.ico from your site root even with no link tag present, and a 404 there is a wasted request on every first visit. It costs a few kilobytes and remains the fallback for older browsers, feed readers and desktop shortcut icons.
Can I just rename a PNG to .ico?
No. The extension does not change the bytes, and while some browsers sniff the content and cope, others refuse it, and nothing can select a size from a file that only contains one. The container structure is the format.
What size PNG should I upload?
256px square or larger. The largest image inside an ICO is 256, so anything bigger only helps the downscaling be cleaner. Below 256 the largest entry is being upscaled, which never adds detail.
Which sizes should go inside it?
16, 32 and 48 as a baseline: 16 and 32 for browser tabs and bookmarks, 48 because Google only considers favicons whose size is a multiple of 48 when choosing the icon for a search result. 64 upwards is for desktop shortcuts and high-DPI displays.
Does ICO compress the images?
Each entry here is stored as a PNG payload, so each one is losslessly compressed. A seven-size file is still typically well under 100 KB, and dropping the 128 and 256 entries roughly halves it if that matters.