Case converter
Switch between upper, lower, title, sentence, alternating and inverse case.
Paste text, pick a case and the box is rewritten in place. Works with accented letters and non-Latin alphabets.
Runs entirely in your browser. Your text is never uploaded — open DevTools, Network tab, and you will see zero requests while you use this tool.
How to use it
- Paste the text you want to convert.
- Press the case you need — the text is replaced immediately.
- Press Copy to take the result.
What this tool does
Paste text, press a button, and the box is rewritten in place. Six conversions are available:
- UPPERCASE — every letter capitalised.
- lowercase — every letter reduced.
- Title Case — first letter of each word capitalised.
- Sentence case — first letter after each terminal punctuation mark capitalised, the rest lowered.
- aLtErNaTiNg — case flips letter by letter.
- iNVERSE — each letter swapped to the opposite case.
Conversion is Unicode-aware, so Cyrillic, Greek, Turkish and accented Latin letters convert properly rather than being left untouched. Digits, punctuation and emoji pass through unchanged.
Examples
| Input | Mode | Output |
|---|---|---|
| the QUICK brown Fox | lowercase | the quick brown fox |
| the QUICK brown Fox | UPPERCASE | THE QUICK BROWN FOX |
| the QUICK brown Fox | Title Case | The Quick Brown Fox |
| hello there. how are you? fine. | Sentence case | Hello there. How are you? Fine. |
| why not | aLtErNaTiNg | wHy nOt |
| Hello World | iNVERSE | hELLO wORLD |
A common workflow: someone sends a paragraph typed with caps lock on. Press lowercase to flatten it, then Sentence case to restore normal capitalisation. Proper nouns will need a manual fix — no tool can tell that bill should have been Bill from context alone.
Title Case in AP, APA and Chicago style
Title Case here is the mechanical version: capitalise every word. Publishing style guides are pickier, and the differences matter if you are writing for a publication or formatting a reference list.
All three guides agree on the basics — capitalise the first and last word of the title, and capitalise nouns, pronouns, verbs, adjectives and adverbs. They disagree about the short words in between.
| Word type | AP | APA (7th ed.) | Chicago |
|---|---|---|---|
| Articles: a, an, the | lowercase | lowercase | lowercase |
| Coordinating conjunctions: and, but, or, nor, for, yet, so | lowercase | lowercase | lowercase |
| Short prepositions: of, in, on, to, at | lowercase under 4 letters | lowercase under 4 letters | lowercase at any length |
| Long prepositions: between, through, against | Capitalised (4+ letters) | Capitalised (4+ letters) | lowercase |
| Word after a colon | Capitalised | Capitalised | Capitalised |
Hyphenated compound: Well-Being | capitalise both parts | capitalise both parts | capitalise both unless the second part is an article or preposition |
| to as an infinitive marker | lowercase | lowercase | lowercase |
The same title under each rule:
- AP:
What to Look For in a Walk Through the City - APA:
What to Look for in a Walk Through the City - Chicago:
What to Look for in a Walk through the City
Note the split on Through: AP and APA capitalise prepositions of four letters or more, Chicago lowercases prepositions regardless of length. AP also capitalises For here because it treats it as part of the verb phrase, while APA lowercases it as a short preposition. Also worth knowing: APA uses title case only for the titles of works inside your text; the reference-list entry itself uses sentence case, capitalising only the first word, the word after a colon, and proper nouns.
Because the correct choice depends on which word is a preposition and which is part of a phrasal verb, run the mechanical Title Case first and then lowercase the handful of short words your style guide wants down.
When you need it
- Fixing caps lock. A message or a form entry typed entirely in capitals, restored in two clicks.
- Imported data. Names and cities from an old system often arrive as
JOHN SMITH; Title Case makes a mailing list presentable. - Headlines and headings. Getting an H1 into house style before it goes into the CMS.
- Academic references. Converting a copied title from title case to sentence case for an APA reference list.
- Code and config. Normalising labels or keys before turning them into constants.
- Toning down shouting. Marketing copy delivered in all caps reads calmer in sentence case.
Doing it without this tool
- Microsoft Word: select the text and press
Shift+F3to cycle lowercase → Sentence case → UPPERCASE, or use Home → Change Case for the full menu including tOGGLE cASE. - Google Docs: Format → Text → Capitalisation, which offers lowercase, UPPERCASE and Title Case.
- Excel and Google Sheets:
=UPPER(A1),=LOWER(A1),=PROPER(A1). Note thatPROPERcapitalises after every non-letter, soo'neillbecomesO'NeillandABC-123stays split. - Notepad++: Edit → Convert Case to, with shortcuts
Ctrl+Ufor lowercase andCtrl+Shift+Ufor uppercase. - Command line:
tr 'a-z' 'A-Z' < in.txtfor ASCII uppercase, orawk '{print toupper($0)}'. In PowerShell,$text.ToUpper().
The gap in all of them is Sentence case across a long text: Word handles it, but Sheets and the shell need a formula or a script, which is why pasting into a browser tab is usually quicker.
Privacy: your text never leaves your browser
The conversion is a few lines of JavaScript running locally. No upload, no server, no logging, no storage. The text exists only in the box until you close the tab.
This is the usual reason to prefer a local tool for case conversion: the text being fixed is often a list of real customer names or an internal document, and pasting either into an unknown server is a problem you do not need.
Related tools
Frequently asked questions
Title Case capitalises every word, which suits headlines. Sentence case capitalises only the first letter of each sentence, which suits normal prose and APA reference lists.
Articles (a, an, the) and coordinating conjunctions (and, but, or) are always lowercase unless they start or end the title. Prepositions depend on the style guide.
AP capitalises prepositions of four letters or more, so it writes "Through". Chicago lowercases prepositions no matter how long they are, so it writes "through".
No. APA uses sentence case for the titles of works in the reference list, capitalising only the first word, the word after a colon, and proper nouns. Title case is used for those titles inside your text.
Yes. Case rules are applied with full Unicode support, so Cyrillic, Greek and accented Latin letters convert correctly.
Use the browser undo shortcut inside the text box, or paste the original text again. Nothing is overwritten outside the page.
No. Sentence case lowercases everything except sentence starts, so names like Paris or Bill need a manual capital afterwards.