Case converter

Paste text, pick a case. Sentence, title, upper, lower, camelCase, snake_case — plus line sorting, duplicate removal, find and replace and a live word count. Nothing you paste leaves this page: every conversion runs in your own browser.

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Programmer cases

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Paste some text and choose a conversion.

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Nothing you paste leaves your browser — every conversion runs on this page. Check this before you rely on it. This text converter is provided free and without warranty, and its results are not professional advice.

Which case do you actually want?

Three of these get confused constantly. Sentence case capitalises the first word of each sentence and nothing else, which is how ordinary prose is written. Title Case capitalises most words but leaves short joining words alone, which is how headlines and book titles are written. Capitalising Every Single Word is neither, and is the thing people usually produce by accident when they meant title case.

If you are fixing a paragraph that arrived in all caps, you want sentence case. If you are fixing a heading, you want title case. If you are naming a variable, skip both and go to the programmer cases below.

What a converter cannot know

Sentence case lower-cases everything and then raises the first letter of each sentence. It has no way to tell that "paris" is a city rather than plaster of paris, or that "ios" is a product name — so proper nouns come back lowercase and you have to fix them by hand. Any tool that claims otherwise is guessing from a word list, and guessing wrong is worse than not guessing.

The same limit applies in reverse to title case: NASA becomes Nasa, because the text was lower-cased first so that shouted input comes back readable. That trade is deliberate. Leaving capitals alone would mean pasting HELLO WORLD and getting HELLO WORLD straight back, which is the single most common thing people paste in.

Why the text stays in your browser

The conversion happens in JavaScript on the page you are already looking at. There is no upload, no API call and no server that could log what you typed — the site makes no external requests at all, which you can confirm in your browser's network tab.

That is not a privacy flourish, it is the reason this kind of tool is usable at work. People paste contracts, patient notes, unpublished copy and half-written resignation letters into case converters. A tool that posts that to a server is one incident away from being a problem, and most of them do.

Every case, on the same sentence

The same phrase through each conversion. These are generated by the code the buttons run, so what is printed here is what you will get.

Case	Result	Where you see it
Sentence case	`The quick brown fox jumps over the lazy dog`	Body copy, email, UI labels in most modern style guides
lower case	`the quick brown fox jumps over the lazy dog`	Emails, tags, slugs, database keys
UPPER CASE	`THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG`	Acronyms, code constants, short emphatic labels
Title Case	`The Quick Brown Fox Jumps Over the Lazy Dog`	Headlines, book and article titles, print style
aLtErNaTiNg	`tHe qUiCk bRoWn fOx jUmPs oVeR ThE LaZy dOg`	Nothing serious — mockery, mostly
InVeRsE	`THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG`	Undoing a caps-lock accident
camelCase	`theQuickBrownFoxJumpsOverTheLazyDog`	JavaScript, Java and Swift variables and methods
PascalCase	`TheQuickBrownFoxJumpsOverTheLazyDog`	Class and type names; exported names in Go
snake_case	`the_quick_brown_fox_jumps_over_the_lazy_dog`	Python and Ruby variables; SQL columns
kebab-case	`the-quick-brown-fox-jumps-over-the-lazy-dog`	URL slugs, CSS class names, npm packages
CONSTANT_CASE	`THE_QUICK_BROWN_FOX_JUMPS_OVER_THE_LAZY_DOG`	Constants and environment variables

Common questions

How do I change text from all caps to normal?

Paste it in and click Sentence case. Every letter is lower-cased and the first letter of each sentence is raised again. Proper nouns and names stay lowercase and need fixing by hand, because nothing in the text identifies them.

Is my text uploaded anywhere?

No. Every conversion runs in your browser. Nothing is transmitted to us, nothing is stored, and closing the tab discards it. The site makes no external requests of any kind.

What is the difference between title case and capitalising each word?

Title case leaves short joining words — a, an, the, and, of, to, in — in lowercase unless they are the first or last word. Capitalising each word raises all of them, which reads as a mistake in a headline.

Is there a limit on how much text I can convert?

Only your browser's memory. There is no server-side limit because there is no server involved. Documents of a few hundred thousand words convert without a noticeable pause.