Case Converter
Paste text once and switch it between six letter cases with the buttons above the box. No retyping, no find-and-replace, no formatting menus buried three levels deep.
The sentence-case and title-case conversions here handle the two things naive converters get wrong: apostrophes inside words, and the standalone pronoun "I". Both are covered below with worked examples.
Need styled letters rather than a case change? Try small caps
Every Case, Same Sentence
One input run through all six conversions so you can see which one you actually want before you paste anything long.
| Input | Output | What it shows |
|---|---|---|
| the quick brown fox | THE QUICK BROWN FOX | All letters raised; spacing and punctuation untouched. |
| THE QUICK BROWN FOX | the quick brown fox | All letters lowered — the usual first step in cleaning data. |
| the quick brown fox | The Quick Brown Fox | Every word capitalised, the rest of each word lowered. |
| THE QUICK BROWN FOX. IT JUMPED. | The quick brown fox. It jumped. | Each sentence gets one capital; the rest is lowered. |
| the quick brown fox | tHe QuIcK bRoWn FoX | Case alternates on letters only, so spaces never break the rhythm. |
| The Quick Brown Fox | tHE qUICK bROWN fOX | Every letter swaps case — the caps-lock rescue. |
| don't stop believing | Don't Stop Believing | The apostrophe does not start a new word: "Don't", not "Don'T". |
| i think i am ready. i am. | I think I am ready. I am. | The standalone pronoun "I" is restored, which most converters miss. |
How Each Conversion Is Defined
Uppercase and lowercase are unambiguous. The other four involve decisions, and here are the ones this tool makes.
Title case capitalises the first letter of every word
The text is lowered, then the first letter of each word is raised. Words are matched with a Unicode-aware pattern that includes apostrophes, so "don't" becomes "Don't" rather than "Don'T". This is "start case" — it does not apply the small-word rules of AP or Chicago style.
Sentence case capitalises after terminal punctuation
The text is lowered, then the first letter of the text and of anything following a full stop, question mark, exclamation mark or line break is raised. The standalone pronoun "I" and its contractions are restored afterwards.
Alternating case counts letters, not characters
Spaces and punctuation do not consume a turn in the alternation, so the pattern stays visually regular across word boundaries. Output starts lowercase, which is the convention the mocking-text meme uses.
Inverse case swaps every letter
Uppercase becomes lowercase and vice versa, with everything else untouched. This is the fastest fix for a line typed with caps lock on when you meant to hold shift for the first letter.
Six Cases Side by Side
The same messy input through every conversion. The rightmost column tells you which situation each one is for.
Shared input: tHE qUICK bROWN fOX. it JUMPED over.
| Transformation | Result | Reach for it when |
|---|---|---|
| UPPERCASE | THE QUICK BROWN FOX. IT JUMPED OVER. | You need emphasis, headers or a shouted line. |
| lowercase | the quick brown fox. it jumped over. | You need to normalise data or calm down all-caps text. |
| Title Case | The Quick Brown Fox. It Jumped Over. | You are writing a heading, title or menu label. |
| Sentence case | The quick brown fox. It jumped over. | You are rescuing a paragraph typed with caps lock on. |
| aLtErNaTiNg | tHe QuIcK bRoWn FoX. iT jUmPeD oVeR. | You want the mocking-text meme effect. |
| iNVERSE cASE | The Quick Brown Fox. IT jumped OVER. | You hit caps lock instead of shift and need it swapped. |
Where Case Conversion Gets Opinionated
Case is more culturally specific than it looks. These are the places where any converter has to choose, including this one.
Title case is not the same as headline style
Editorial styles lowercase short prepositions and articles — "The Wind in the Willows". This tool capitalises every word, which is what most people want for menu labels and short titles but is not AP or Chicago style.
Acronyms are destroyed by sentence case
Lowering the text first means NASA becomes Nasa and HTML becomes Html. There is no way to distinguish an acronym from shouting without a dictionary, so check acronyms after converting a paragraph.
Proper nouns are not detected
Sentence case has no knowledge of names, so "paris" stays lowercase unless it starts a sentence. Title case is the safer choice when your text is mostly names.
Locale affects a few letters
Turkish distinguishes dotted and dotless i, so uppercasing "i" gives a different result under Turkish rules. The conversions here use your browser's default locale handling, which is correct for English and most Latin-script languages.
Where Case Conversion Saves Time
Most word processors hide case conversion behind a menu and only offer three of these six. Pasting into a browser tab is usually faster.
Word and Google Docs
Both offer sentence, upper, lower and title case, but their title case capitalises differently and neither offers alternating or inverse case. Paste here when you need the other three.
Spreadsheets
UPPER, LOWER and PROPER exist as formulas, but they need a helper column and a paste-values step. For a one-off conversion, pasting a column here and back is quicker.
Social posts and headlines
Title case for headlines, sentence case for body copy. All-caps posts are throttled by some platforms' spam heuristics, so use uppercase sparingly.
Code and data cleaning
Lowercasing is the standard first step when normalising user input for comparison. Do it here for a quick check before committing to it in code.
Common Reasons to Change Case
Rescuing caps-lock text
A paragraph typed with caps lock on is fixed by sentence case in one paste. Inverse case is the right choice when only the first letter of each word was wrong.
Standardising headings
Running every heading in a document through title case makes an inconsistent set uniform in seconds.
Preparing data for comparison
Lowercasing both sides before comparing strings avoids a whole class of "why does this not match" bugs.
Meme formatting
Alternating case is the mocking-text format. It is a joke, not a style — one line is funny, a paragraph is not.
Frequently Asked Questions
Related Text Tools
Uppercase Converter
Convert text to ALL CAPS without retyping it.
Lowercase Converter
Convert shouty or mixed-case text to lowercase.
Title Case Converter
Capitalise Every Word For Headings And Titles.
Sentence Case Converter
Fix all-caps text back into normal sentences.
Alternating Case Converter
mAkE tExT lIkE tHiS in one click.
Backwards Text Generator
Turn any sentence into backwards text, character by character.
Upside Down Text Generator
Flip text 180° with rotated Unicode lookalikes.
Mirror Text Generator
Create reflected text that reads like a mirror image.