Hold Alt, type the number on the numeric keypad, let go. The leading zero picks which character set Windows reads the number from, so the same character often has two codes.
Click any key to copy the character.
Nothing matches. Try a different word, or switch the keyboard language above.
Alt + 0176 is ° but Alt + 176 is ░. Codes 32 to 126 are the plain keyboard characters and come out the same either way.
Check the language indicator in the taskbar. The code is read from the character set of the keyboard language that is active while you hold Alt, so the same code gives é in English and י in Hebrew.
Press Win + . for the symbol panel, or run charmap. In Word, type the hex code and press Alt + X: 2014 becomes an em dash.
Most programs wrap them around, so Alt + 257 types the same thing as Alt + 1. Word and WordPad read them as Unicode instead.