How to Change Text Case

You have written a headline in ALL CAPS and need it back. You have a column of names in inconsistent capitalisation. You are converting a label into a variable name. Changing text case is one of those small chores that is tedious by hand and instant with a tool — but only if you know which case you actually want. This guide covers all of them, and the rules that make title case genuinely tricky.

The everyday cases

• UPPERCASE — every letter capitalised. Use sparingly: it reads as shouting, and it is measurably harder to read in long stretches, because we recognise words partly by their shape and capitals flatten every word into the same rectangle.
• lowercase — no capitals at all. Essential for URLs, email addresses, tags and anything case-sensitive that should not be.
• Sentence case — only the first letter capitalised, plus proper nouns. “How to change text case”
• Title Case — the main words capitalised. “How to Change Text Case”
• Capitalised Every Word — every word capitalised without exception, including the and of. Simple to compute, but not actually correct title case.
• aLtErNaTiNg — used exclusively for sarcasm on the internet.

Title case vs. sentence case

This is a real editorial decision, not just a formatting one — and it is worth being deliberate about, because inconsistency looks careless.

Sentence case is the modern default. It is easier to read, easier to apply consistently, and it handles long headings gracefully. Most tech companies and modern publications have moved to it, and every major design system now recommends it for interface text.

Title case feels more formal and traditional. Newspapers, academic citations and book titles still use it. It also, in practice, makes headlines slightly harder to skim.

Pick one and apply it everywhere. A page with some headings in title case and others in sentence case looks unfinished, and readers notice even if they cannot say why.

The actual rules of title case

Proper title case is not simply capitalising every word. The convention is:

• Capitalise the first and last words, always.
• Capitalise nouns, verbs, adjectives, adverbs and pronouns.
• Lowercase short articles (a, an, the), coordinating conjunctions (and, but, or, nor) and short prepositions (in, on, at, to, of, for).

So it is “The Rise and Fall of the Roman Empire” — with and, of and the second the in lowercase — not “The Rise And Fall Of The Roman Empire.”

And there are genuine ambiguities. Style guides disagree on where to draw the line for prepositions: some lowercase everything under four letters, others under five, so with and from land differently depending on whose rules you follow. There is no single correct answer, only a consistent one.

This is why automatic title-case conversion is imperfect. A tool cannot always tell that “up” is a preposition in “walk up the hill” but part of a verb in “give up hope.” Treat the output as a strong first draft, and read it.

Programming cases

Since most languages forbid spaces in identifiers, programmers invented several ways to glue words together — and which one you use is dictated by the language, not by taste.

• camelCase — first word lowercase, subsequent words capitalised: userFirstName. Standard for variables in JavaScript, Java and C#.
• PascalCase — every word capitalised, including the first: UserFirstName. Used for class and component names, which is why React components are written this way.
• snake_case — lowercase words joined by underscores: user_first_name. The convention in Python, Ruby and SQL.
• kebab-case — lowercase words joined by hyphens: user-first-name. Used for CSS classes, HTML attributes, and URLs.
• SCREAMING_SNAKE_CASE — uppercase with underscores: MAX_RETRY_COUNT. Universally used for constants.

One rule that matters beyond programming: URLs use kebab-case, never snake_case. Search engines treat a hyphen as a word separator and an underscore as a joiner — so merge-pdf-files is read as three words and merge_pdf_files may be read as one. This is a genuine, if modest, SEO difference.

Case traps worth knowing

• Uppercasing loses information. Convert to ALL CAPS and you cannot get back to the original — the tool has no way to know which letters were capitals. Always keep the original.
• Acronyms break naive conversion. Sentence case turns NASA into Nasa. Check the output when your text contains acronyms.
• Names are not always simple. McDonald, O'Brien, van der Berg, iPhone— none of them follow the “capitalise the first letter” rule.
• The Turkish i. A famous edge case: in Turkish, the uppercase of i is İ (with a dot), not I. Locale-unaware case conversion corrupts Turkish text, and this has broken real software.

Frequently asked questions

Should headings use title case or sentence case? Sentence case is the modern default and is easier to read. Either is fine — consistency is what matters.

Can I undo an uppercase conversion? Not perfectly. The original capitalisation is gone. Keep the source text.

Which case should I use for URLs? Lowercase kebab-case.

Is title case just capitalising every word? No — short articles, conjunctions and prepositions stay lowercase.

Convert text case now

Use our Case Converter to switch between uppercase, lowercase, sentence case, title case and more instantly in your browser — nothing is uploaded. Turning a title into a URL? The Slug Generator produces proper lowercase kebab-case slugs.