German Umlauts and ß

Alt+0223 on Windows. In Outlook, Ctrl+Shift+&, then s.

Tap a letter to copy it, or see below how to type the umlauts and ß.

Umlauts

The sharp s, and its capital.

Alt codes from the Windows-1252 and code page 437 tables; Outlook shortcuts from Microsoft's list for international characters.

Letter	Unicode name	Accent	Windows Alt code	Outlook	HTML	Code point
ä	LATIN SMALL LETTER A WITH DIAERESIS	umlaut	`Alt+0228` or `Alt+132`	`Ctrl`+`Shift`+`:`, then `a`	`ä`	`U+00E4`
ö	LATIN SMALL LETTER O WITH DIAERESIS	umlaut	`Alt+0246` or `Alt+148`	`Ctrl`+`Shift`+`:`, then `o`	`ö`	`U+00F6`
ü	LATIN SMALL LETTER U WITH DIAERESIS	umlaut	`Alt+0252` or `Alt+129`	`Ctrl`+`Shift`+`:`, then `u`	`ü`	`U+00FC`
Ä	LATIN CAPITAL LETTER A WITH DIAERESIS	umlaut	`Alt+0196` or `Alt+142`	—	`Ä`	`U+00C4`
Ö	LATIN CAPITAL LETTER O WITH DIAERESIS	umlaut	`Alt+0214` or `Alt+153`	—	`Ö`	`U+00D6`
Ü	LATIN CAPITAL LETTER U WITH DIAERESIS	umlaut	`Alt+0220` or `Alt+154`	—	`Ü`	`U+00DC`
ß	LATIN SMALL LETTER SHARP S	—	`Alt+0223` or `Alt+225`	`Ctrl`+`Shift`+`&`, then `s`	`ß`	`U+00DF`
ẞ	LATIN CAPITAL LETTER SHARP S	—	none	—	`ẞ`	`U+1E9E`

ä, ö and ü are the umlauts. The Council for German Orthography treats them, and ß, as letters of their own.
ß is used only after long vowels and diphthongs, and not at all in Switzerland and Liechtenstein.
The capital ẞ became an official letter of the German alphabet on 29 June 2017.
If umlauts aren't available, ä ö ü are written ae, oe, ue, though that's best avoided, especially in names.

Windows: hold Alt and type the code on the numeric keypad: ä 0228, ö 0246, ü 0252. The table below has every code.
Mac: press and hold the letter and the accent menu shows the accented letters; click one or press the number shown under it. Accent menus aren't available in every app.
iPhone: touch and hold the letter, then slide to the accented letter you want.
Android (Gboard): touch and hold the letter to see the accents.
Outlook: Ctrl+Shift+:, then a for ä; Ctrl+Shift+:, then o for ö; Ctrl+Shift+:, then u for ü.
Microsoft Office: type the code (00E4 for ä) and press Alt + X. PowerPoint doesn't convert codes this way.
HTML: ä for ä, ö for ö, ü for ü.

How do I type ß?

Alt+0223 on Windows. In Outlook, Ctrl+Shift+&, then s.

What can I write instead of ä, ö and ü?

ae, oe and ue, if the umlauts aren't available.

Is there a capital ß?

Yes: ẞ (U+1E9E), an official letter since 29 June 2017.