keyboard - How do you type Unicode characters using hexadecimal codes?

This is in Windows, but answers for other operating systems can be handy to others.

Most guides say something to the effect of "hold down the Alt key and type in the code on the keypad". This works fine for decimal codes (like 65 for 'A'), but not for hexadecimal codes (like U+0041 for 'A').

Some applicatons provide other facilities that will allow hexadecimal Unicode character codes to be typed and then transformed. Word allows you to type the code (such as 200f) and then convert it to Unicode by typing Alt-X.

I'm looking for a general method of doing this that will work with the standard input.

Answer

harrymc's answer is good, providing you're able/allowed to change the registry settings.

If not, you can use the Windows Calculator Accessory to convert from hexadecimal to decimal. The default mode won't do this: XP and Vista have a "Scientific mode, whereas Windows 7, 8, 8.1 and 10 have a "Programmer" mode.

Select Hex base, and then type in your hexadecimal number. Then change to Dec base to see the equivalent value in decimal. That's the number you need to type into your numeric keypad while holding down the Alt key.

This might depend on the input language, and you might need to prefix a zero to the decimal value.