Conversion runs as you type and stays on your device - the text is never uploaded, which makes it safe for unpublished drafts, internal docs and AI prompts. Title Case follows AP/Chicago: minor words like a, an, the, and, of, in, on, to stay lowercase unless they are the first or last word. Sentence case lowercases everything and re-capitalizes the start of each sentence, preserving the pronoun "I" and its contractions. Acronyms in all-caps (NASA, HTML) are left intact in Title and Capitalize modes so you don't have to retype them.
Case Converter
English onlyRuns entirely in your browser - no upload, no sign-up.
Convert every letter to its uppercase form (the cat -> THE CAT).
Input text
Converted text
Paste text to convert to UPPERCASE, lowercase, Title Case or Sentence case
Characters: 0Words: 0Lines: 0
What is a case converter?
A case converter changes the letter case of text without retyping it. This tool runs seven conversions in your browser: UPPERCASE, lowercase, Title Case (AP/Chicago style), Sentence case, Capitalize Each Word, aLtErNaTiNg cAsE and iNvErSe CaSe. Paste a sentence, a heading or a whole article, pick a mode, and copy the result.
How to use
- 1Paste your text. Type or paste the text you want to convert into the left box. The tool works on a word, a sentence, or thousands of lines at once.
- 2Pick a case. Tap UPPERCASE, lowercase, Title Case, Sentence case, Capitalize Words, aLtErNaTiNg or iNvErSe. The converted text appears live on the right.
- 3Copy or chain. Press Copy to put the result on your clipboard, or Use as input to pipe it back into the input box and apply another conversion (lowercase first, then Title Case).
Who it's for
- Writers and editors fixing a headline pasted in shouty caps, or normalising a quote that arrived in
SENTENCE CASE. - Students and bloggers applying Title Case to article titles and chapter headings without memorising the AP rule list.
- Developers cleaning up CSV columns, log lines or label copy before it ships - paste a column, lowercase it, copy back.
- AI prompters and content teams normalising LLM output that mixes cases, or generating playful aLtErNaTiNg text for social posts.
FAQ
Is this case converter free?
Yes - 100% free, no sign-up and no character limits. Conversion happens in your browser, so it's also fast on very large pastes.
Is my text uploaded anywhere?
No. Everything runs locally in your browser and never reaches a server, so it's safe for confidential drafts, contracts and AI prompts.
What is the difference between Title Case and Capitalize Each Word?
Title Case follows AP/Chicago style: short words like a, an, the, and, of, in, on, to stay lowercase unless they're the first or last word. Capitalize Each Word is the naive form - it capitalises every single word, even the small ones. Pick Title Case for headlines and book titles, Capitalize for slugs or labels.
How does Sentence case decide where a sentence ends?
It lowercases the whole text, then re-capitalises the first letter after a period, exclamation mark or question mark that is followed by whitespace (so abbreviations like <code>i.e.</code>, <code>e.g.</code> and <code>U.S.A.</code> stay intact internally - the periods between letters don't reset capitalisation). The pronoun "I" and contractions (I'm, I'll, I've, I'd) are preserved capitalised. Mid-text abbreviations followed by a space, like "i.e. ", are still treated as sentence breaks - there's no reliable way to disambiguate without a dictionary.
Does it handle accents, German ß, Greek, Cyrillic?
Yes. UPPERCASE and lowercase use the browser's Unicode case mapping, so é -> É, ñ -> Ñ, ß -> SS and я -> Я all work. CJK scripts, Arabic and Hebrew have no concept of letter case, so they pass through unchanged.
Will it break my acronyms like NASA or HTML?
No. Title Case and Capitalize Each Word detect tokens that are entirely uppercase (two letters or more) and leave them as-is, so a paste containing NASA, HTML or IBM stays exactly that way.
What is aLtErNaTiNg case for?
It's the mocking SpongeBob meme style - aLtErNaTiNg lowercase and uppercase letter by letter. Useful for social posts and chat humour. Non-letter characters (spaces, punctuation) pass through and don't break the rhythm.
Can I undo or chain conversions?
Yes. The input box is never modified - your original text stays put. Press Use as input to push the current result back into the input box, then apply another mode (for example, lowercase first, then Title Case).