Convert upper and lower case

Each letter in the English alphabet can be written in both upper case (A, B, C, ...) and lower case (a, b, c, ...). Upper case letters are often called capital letters, and the process of writing letters, either all or just some of them, as capital letters is called capitalisation.

The most common convention is to start sentences and proper nouns with capital letters, and use lower case for the rest of the letters. Sometimes text is written with only capital letters for stylistic reasons, for emphasis, or to show that something is loud (e.g. a scream).

With the tool on this page you can do the following.

  1. Convert all letters to upper case (capital letters).
  2. Convert all letters to lower case.
  3. Convert the first letter in each sentence to a capital letter.
  4. Convert the first letter in each word to a capital letter.
  5. Convert upper case letters to lower case, and lower case letters to upper case.

Note that #3 and #4 only changes the first letter in each word or sentence. The remaining letters stay the same to avoid that names are incorrectly rewritten with lower case letters.

#3 uses dots (.), exclamation marks (!) and question marks (?) to detect the start and end of each sentence, but the tool is often able to handle sentences that contain parentheses and abbreviations correctly.