Upload an image, pick sizes (16/32/48 etc), and download a multi-size favicon.ico. Works fully client-side.
Tip: start with a square image (e.g. 512×512). Text often becomes unreadable at 16×16.
It builds a favicon.ico file that contains multiple icon sizes (e.g. 16×16, 32×32, 48×48). Browsers pick the most suitable size automatically.
No. Everything runs locally in your browser using a canvas. Your image never leaves your device.
At 16×16 there are very few pixels to work with. Bold shapes and simple marks survive; thin strokes and detailed text usually don’t.
Put favicon.ico in your site root (so it’s reachable at /favicon.ico). Optionally add <link rel="icon" href="/favicon.ico"> in your page head.