Case converter
Convert your text to uppercase, lowercase, sentence case, or title case following English capitalization rules, and undo the change whenever you like.
You can also drag a .txt, .md, .csv, or .docx file onto the box. It is not uploaded to any server.
Convert to
Your text is almost all capitals
Switch it to Sentence case so it reads well. Proper nouns and acronyms will turn lowercase: add them under “What to keep.”
What to keep
For Sentence case and Title Case. Whatever you select stays exactly as you typed it.
Separate them with commas. They apply to Sentence case and Title Case.
Because almost all of the text is in capitals, acronyms cannot be recognized on their own. Use the word list.
Some capitals that are usually kept were lost
How does the conversion work?
- Locale: English rules are used. “i” always becomes “I” (no Turkish dotted I) and “ß” becomes “SS” in uppercase.
- Sentence case: capital at the start, after a period, question mark, or exclamation mark, and after every line break. “Mr.,” “Dr.,” “e.g.,” and initials do not end a sentence; “etc.” does only if a capital follows. Links and email addresses are left untouched. The pronoun “I” is always capitalized.
- Title Case: capital on every word except short articles, prepositions, and conjunctions (a, an, the, and, but, or, for, at, by, in, of, on, to, up…), which stay lowercase unless they are the first or last word or follow a colon.
- Variable names: each line becomes one name; words are split on spaces, hyphens, underscores, or capitals inside a word.
How to use it
- Type or paste your text in the box. You can also open a .txt or .docx file.
- Pick the conversion: UPPERCASE, lowercase, Sentence case, Title Case, or another. The result updates instantly.
- Adjust what to keep (acronyms, names, brands) or turn on “Remove accents.”
- Copy the result or download it as a .txt. If you would rather change the same box, turn on “Apply to the same box” and use Undo if you make a mistake.
Frequently asked questions
How does Sentence case work?
It capitalizes the first letter of each sentence: at the start of the text, after a period, question mark, or exclamation mark, and after every line break. The pronoun “I” is always capitalized, and abbreviations such as “Mr.” or “Dr.” do not end a sentence. Links and email addresses are left alone.
What does Title Case do?
It capitalizes every word except short articles, conjunctions, and prepositions (a, an, the, and, but, or, for, at, by, in, of, on, to, up…), which stay lowercase unless they come first, come last, or follow a colon. So “the lord of the rings: the return of the king” becomes “The Lord of the Rings: The Return of the King.” This follows the common AP-style rule; other style guides handle longer prepositions differently.
How do I keep acronyms and brand names as they are?
Under “What to keep” you can turn on “Acronyms in capitals” (NASA, PDF), “Capitals inside words” (iPhone, YouTube), and “Words that already start with a capital” (proper nouns). You can also type a list of words that always keep their spelling. If your whole text is in capitals, acronyms cannot be recognized on their own, so use the list.
What happens with accents and special letters?
“Remove accents” strips accent marks and diaeresis, so “Müller’s façade” becomes “Muller’s facade.” When you convert to uppercase, the German “ß” becomes “SS.”
Does it work for variable names?
Yes. camelCase, PascalCase, snake_case, kebab-case, and CONSTANT_CASE turn each line into one name: “my name is ana” becomes “myNameIsAna.” For code, turn on “Remove accents.”
Is my text sent to a server?
No. The conversion happens in your browser and your text never leaves your device.
When to use capital letters in English
- At the start of a text and after a period. Also after a question mark or exclamation mark that ends the sentence.
- Proper nouns: people, places, brands, and countries (Ana, New York, Canada).
- The pronoun “I” and its contractions (I’m, I’ll).
- Days and months: Monday and September are always capitalized in English.
- Acronyms: NASA, PDF, FBI. Acronyms that have become ordinary words are lowercase (radar, laser).
- Job titles are capitalized only before a name (President Lincoln) and stay lowercase otherwise (the president).
Text in all capitals
Text written entirely in capitals is harder to read and is usually taken as shouting online. Paste it here and switch it to “Sentence case” to get the capitals back where they belong. Then check the proper nouns: they cannot be guessed, so they turn lowercase unless you add them to the list of words to keep.
If you also need to clean up spacing or count what you wrote, try Character counter or Sort lines.
Updated on September 29, 2026