Typing Special Characters with Alt Codes on Windows and Mac
On Windows, some special characters can be typed using the keyboard's numeric keypad (numpad) with a method called an "Alt code". In this method, you hold down the Alt key while typing a specific sequence of numbers on the numpad; releasing the Alt key types the corresponding character on screen. For example, Alt+0169 produces the copyright symbol (©), and Alt+0176 produces the degree sign (°). The biggest downside of this method is that most laptops don't have a separate numpad, and some numbers need to be used together with the Fn key, which makes the process cumbersome in practice.
On Mac, the system works differently: many common symbols have a direct key combination defined (like Option+2 for ™, Option+G for ©, Option+0 for the degree sign — these can vary by country keyboard layout), and there's also a system tool called "Character Viewer" (opened with Control+Command+Space) that lets you search among emoji and symbols and insert the character you want directly. This tool is organized by category, but its interface isn't as quick to scan as a reference page designed specifically for the web.
The common problem with these methods is that they require memorization: remembering a four-digit code for a symbol you don't use often, or searching in a system tool, usually takes longer than just copying and pasting that symbol from a source where it already exists. Alt codes can be a practical shortcut only for one or two symbols you use very often (for example, a weather forecaster who constantly types the degree sign); for rarely used, varied symbols, a searchable list organized by category is a much faster solution.
The category lists on this site are designed to meet exactly this need: you can find the symbol you want and copy it with one click, without memorizing a code or learning an operating-system-specific shortcut.