PNG to ICO
Convert PNG to ICO favicon in your browser: one .ico with 16, 32 and 48 px sizes. Free, private, no upload. Made for developers.
About this tool
Every website needs a favicon.ico, and this tool builds a proper one: a single .ico file containing 16x16, 32x32, and 48x48 versions of your PNG, so browsers and Windows always pick a sharp size. The conversion runs entirely in your browser.
Start from a square PNG (512x512 or larger works best). Non-square images are centered on a transparent square rather than stretched. Transparency is fully preserved.
Common uses
- Generate favicon.ico for a website from a logo PNG
- Create Windows application or shortcut icons
- Convert app icons for legacy systems that require .ico
Automate via API
The same conversion is available as a REST endpoint for scripts, pipelines, and backends. POST the file, get the converted file back:
curl -X POST https://formatably.com/api/v1/tools/png-to-ico \ -H "X-Api-Key: YOUR_API_KEY" \ --data-binary @photo.png \ -o photo.ico
Direct requests accept up to 4 MB; the large-file flow handles up to 100 MB. Both are covered in the API documentation · Get an API key
Installing your favicon
On a hand-coded site, place the file at the root of your domain as /favicon.ico and browsers will find it automatically with no HTML changes; that path is requested by convention.
On WordPress, do not upload the ICO at all: the Site Icon setting (Appearance, Customize, Site Identity) wants a square PNG of at least 512x512 and generates every size itself, so give it your source PNG. The ICO from this tool is for sites where you manage the files directly.
On Shopify, upload a 32x32 PNG under Theme settings, Favicon; like WordPress, the platform handles the rest. After deploying a favicon anywhere, hard-refresh or test in a private window, because browsers cache favicons aggressively and the old one can linger for days.
If you keep the file somewhere other than the root, or simply want to declare it explicitly, add this to your page head:
<link rel="icon" href="/favicon.ico" sizes="16x16 32x32 48x48">
PNG notes
PNG is the lossless workhorse: screenshots, logos, UI graphics, and anything needing transparency. Every device and program on earth opens it. The tradeoff is size: photos stored as PNG are several times larger than JPEG.
- PNG is lossless, so converting into PNG never loses quality, but converting a photo to PNG can triple its size.
- Transparency is preserved in PNG; JPG has no transparency at all.
ICO notes
ICO is the Windows icon container used for favicons and application icons. One .ico file holds the same image at several sizes (16, 32, 48 pixels and up) so each context can pick the sharpest fit.
- Browsers accept PNG favicons, but .ico remains the most compatible choice, especially for older browsers and Windows shortcuts.
- Start from a square source image; non-square input is letterboxed onto a transparent square.
Frequently asked questions
What sizes are included in the ICO file?
16x16, 32x32, and 48x48, the sizes browsers and Windows actually use for favicons, tabs, and shortcuts. They are stored as PNG-compressed entries, supported everywhere since Windows Vista.
Do I even need an .ico file, or can I use a PNG favicon?
Modern browsers accept PNG favicons via a link tag, but favicon.ico remains the zero-configuration fallback every browser, crawler, and RSS reader looks for. Shipping both is best practice.
Are my files uploaded to a server?
No. The conversion runs entirely in your browser using WebAssembly and the canvas API; your files never leave your device. There are no ads and no trackers on tool pages. You can verify this yourself: open your browser's developer tools, watch the Network tab while converting, and you will see no upload requests. It even works offline once the page has loaded.
Is there a file size limit?
In the browser there is no hard limit; you are bounded only by your device's memory, and files of a few hundred megabytes are usually fine. The REST API accepts files up to 4 MB in a direct request, or up to 100 MB using the large-file upload flow described in the API docs.
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