There is an easy way to write the German characters ä ö ü and ß on a non-German keyboard: Press NUM on the number pad of your keyboard to activate the NUM-lock. Then press ALT and keep it pressed while you type the code 132 on the number pad. 132 is the code for the letter ä, the a umlaut.
Use the ASCII codes in the following table for the other German letters.
ALT + 132
ALT + 142
ALT + 148
ALT + 153
ALT + 129
ALT + 154
ALT + 225
for
for
for
for
for
for
for
ä
Ä
ö
Ö
ü
Ü
ß
ä – umlaut, small letter
Ä – umlaut, capital letter
ö – umlaut, small letter
Ö – umlaut, capital letter
ü – umlaut, small letter
Ü – umlaut, capital lette
ß – eszett or sharp s
The letters ä ö ü
The umlaut letters ä ö ü are on German computer keyboards. Character encodings are used to render them on a non-German keyboard. If the umlauts are not available they are replaced by ae, oe and ue. Gepäck, Köln and München are typed as Gepaeck, Koeln and Muenchen.
The letter ß
The letter ß represents a voiceless s. Since it is never used at the beginning of a word, it exists only as a small letter. If it is not available for typing or printing, ss is used instead. So the word groß is written as gross.