PNG to ICO Converter
Turn a PNG into a real multi-size .ico favicon — pick your icon sizes, preview
each one, and download. Everything is processed in your browser — nothing is uploaded.
PNG to ICO converter
Drop a PNG file here
or press Enter / click to browse your device
Single PNG · up to 100 MB · validated by file signature
Preview
Drop a PNG to begin — size options and previews will appear here.
How it works
What an ICO file actually is
An .ico file is not a single image but a small container: a 6-byte header followed
by a directory of entries, each describing one embedded image — its width, height, color
depth, size, and where its data lives in the file. Windows, macOS, and browsers read that
directory and pick the entry closest to the size they need, so a single
favicon.ico can serve a crisp 16-pixel browser tab icon and a sharp 256-pixel
desktop tile alike. This page builds that container for you, in your browser, byte by byte.
Which sizes to include
The time-tested trio of 16, 32, and 48 pixels covers the essentials: browser tabs and address
bars (16), the Windows taskbar and desktop icons (32), and larger icon views (48). On modern
high-DPI ("retina") displays, the operating system will upscale a 48-pixel icon and it can
look soft — that is what 64, 128, and 256-pixel entries are for. They add only kilobytes
(PNG compresses flat icon art extremely well), so when in doubt, include them. Favicon
convention: save the result as favicon.ico and reference it from your site's
HTML, or drop it at your domain root where browsers look for it automatically.
PNG-compressed entries, explained
Each size in your ICO is stored as PNG image data rather than the legacy BMP format. This is the modern standard: PNG entries are far smaller and support full alpha transparency, and they work everywhere that matters — Windows Vista and later, macOS, and every current browser. The one honest caveat: software from the Windows XP era (notably Internet Explorer 8 and older) cannot read PNG-compressed entries and needs old-style BMP icons. If you must support those museum pieces, use a legacy converter; for the modern web, PNG entries are correct.
How your PNG becomes each icon
Your file is first verified by its magic bytes (the 8-byte PNG signature), not just its
extension, so a renamed JPEG cannot sneak through. It is then decoded and drawn onto a
square canvas at each selected size with high-quality resampling. Because ICO entries must be
square, a non-square source is scaled to fit and centered on transparency — letterboxed, not
stretched. Each rendering is encoded as PNG, packed into the ICO directory structure with
correct offsets, and offered as a single .ico download. For the sharpest result,
start with a square PNG of at least 256×256 pixels with a little padding around your
mark.
Frequently asked questions
What is an ICO file?
ICO is the classic Windows icon container format, also used for website favicons (favicon.ico). A single .ico file holds several images at different sizes — typically 16, 32, and 48 pixels — and the operating system or browser picks the sharpest one for each context: browser tabs, taskbars, desktop shortcuts, and high-DPI displays.
Which sizes should I include?
The classic trio of 16, 32, and 48 px covers browser tabs, desktop icons, and the Windows taskbar, and it is selected by default here. Add 64 and 128 px for sharper rendering on high-DPI ("retina") displays, and 256 px for large icon views and Windows tiles. Including more sizes makes the file bigger, but even all six sizes usually total well under 1 MB.
Will this favicon work in all browsers?
Yes, in all modern browsers. This tool stores each size as PNG-compressed image data inside the ICO, which Windows Vista and later — and every current browser — supports. Only truly ancient software (Internet Explorer 8 and older, Windows XP-era tools) requires the legacy BMP-based entries; if you still need to support those, you will want a specialized legacy converter.
My PNG is not square — what happens?
ICO entries must be square, so non-square images are scaled to fit inside the target size and centered on a transparent background (letterboxed). For the cleanest favicon, start with a square PNG with some padding around your logo — that is what the preview shows you before you download.
Are my images uploaded anywhere?
No. The PNG is decoded, resized, assembled into the ICO file, and downloaded entirely within your browser. Nothing ever leaves your device, there is no account or queue, and it works offline once the page has loaded.