Case converter
Accidentally left Caps Lock on? Need a headline in Title Case? One click and your text is fixed.
When to use each format
Title Case (every word capitalized) is the go-to choice for video titles, article headlines and slide decks. Sentence case cleans up text typed in a hurry, capitalizing only the first letter after each period. UPPERCASE works for acronyms and callouts, but use it sparingly: online, all caps reads as shouting.
Fix text without retyping it
Instead of retyping a paragraph that came out in the wrong case, paste it above and click the format you need. The converter handles apostrophes and hyphenated words correctly (so "o'clock" becomes "O'Clock" and "well-known" becomes "Well-Known" in Title Case), and you can chain conversions, for example lowercase first, then Sentence case, until the text looks right. The copy button puts the result straight on your clipboard.
The detail that sets Title Case apart
Here the capital fires after a space, but also after a hyphen and an apostrophe: «jean-luc» becomes «Jean-Luc» and «o'clock» becomes «O'Clock». That's the right shape for surnames and for English titles; if you want the capital only after spaces, that one is Capitalize every word.
Two things the program cannot guess
Every format except the swap starts by putting the text into lowercase, so acronyms are lost: «PDF» becomes «Pdf» and «VAT» becomes «Vat». The same happens to proper nouns with sentence case: «Mario» goes back to «mario» and has to be restored by hand. It isn't an oversight, it's that no program can know which words are names and which aren't.
The swap, on the other hand, lowers nothing: it only flips, which is why it's the only one you can apply twice to get back where you started. It's the one you need when Caps Lock was left on, and it has a page of its own: Swap upper/lowercase.
Nearby tools
To stand a text typed all in lowercase back up there is Capitalize sentences, and for titles Capitalize every word. If the text also has its spaces in disarray, it's worth first running it through Remove extra spaces; for a web address, which wants everything lowercase and dashes, there is Make a URL slug.