str.upper
Convert all letters of the string to uppercase.
Python 3.13
str.upper()Return value
A new string; the original is not changed.
Examples
Converting to uppercase
Python 3.13
print('hello'.upper())HELLO
The string gets longer
Python 3.13
word = 'straße'
print(word.upper(), len(word), len(word.upper()))STRASSE 6 7
Details
The length of the string can change: some letters have no single uppercase pair, for example the German ß becomes SS. Digits and punctuation do not change. For case-insensitive comparison, str.casefold is more reliable.