A favicon is 16 by 16 pixels. That's 256 pixels total. Your logo, your brand, your site's entire visual identity squeezed into a space smaller than a thumbnail of a thumbnail. Most designers approach this the wrong way: they take the main logo, shrink it down, and wonder why it looks like a smudge in the browser tab. The problem isn't the tool. It's that most logos were never designed to work at that scale.
A well-designed favicon is almost always a simplified version of the brand. Not the full logo with the wordmark and the tagline and the decorative elements. Just the core mark, the initial, or the most distinctive shape. Think of the favicon for any major website you use regularly. It's almost always a single letter, a simple geometric icon, or a reduced version of the logo that strips everything non-essential.
Why your source image size and shape matter more than you'd expect
The quality of your favicon depends heavily on what you start with, in two ways. First, resolution: dropping a 200 by 200 pixel PNG into the converter and asking it to produce a 16 by 16 output is fine, but it's not ideal. The downsampling algorithm has less information to work with, and the result can look softer than necessary. Start with a 512 by 512 or larger source PNG for the best output at every size. Second, aspect ratio: the converter maps your source directly onto each square icon size, stretching it to fit rather than cropping or padding it. A rectangular logo dropped in as-is will come out visibly squished at every size. Crop or pad your source to a perfect square before converting.
If your source image is a vector SVG, the first step is to convert it to a PNG at a large size before running it through this converter. The SVG to PNG tool handles that, and you can set the output size to 512 by 512 directly. Then bring that PNG here for the ICO conversion.
ICO vs PNG favicons
Every modern browser now supports PNG favicons. Chrome, Firefox, Safari, and Edge will all happily use a PNG file if you point them to one with the link tag. So why bother with ICO at all? Because ICO is still the only format that works reliably across every context where your favicon might appear. Browser bookmarks on older systems, Windows taskbar pinned sites, desktop shortcuts, email clients that display favicon-style icons. The ICO file with multiple embedded sizes is the one format that covers all of those without you having to think about it, which is exactly what this converter's default package is built around: the ICO as the primary reference, with a PNG fallback for each size alongside it.
The one thing this tool doesn't generate is the platform-specific extras: a 180 by 180 Apple touch icon for iOS home screen bookmarks, and typically a 192 by 192 PNG plus a web manifest for Android. If you need those alongside the classic favicon set, the dedicated Favicon Generator tool builds all of it, ICO, Apple touch icon, Android icons and manifest, in one pass.