Case Converter

How to use the case converter

1. Paste or type your text into the box above. Every format updates as you type.
2. Find the format you need. The cards are grouped into text cases for writing, programming cases for code, and two novelty formats.
3. Copy or apply. Clicking a card copies that version to your clipboard. The Apply button in its corner replaces the text in the box instead, so you can chain conversions.
4. Undo if needed. Applying a case is never destructive — Undo restores what was there before.

Nothing is uploaded. All twelve conversions happen in your browser.

When you would need this

Fixing text that arrived in the wrong case. A headline pasted in from a document that was typed in all caps. A spreadsheet column where half the entries are capitalised and half are not. Retyping is slow and introduces typos; converting takes a second.

Writing headlines and titles. Publications specify title case or sentence case in their style guide, and the rules are fiddly enough that people apply them inconsistently. Converting gives you a correct starting point.

Renaming code between conventions. Moving a variable from JavaScript to Python means camelCase to snake_case. Turning a component name into a CSS class means PascalCase to kebab-case. Generating an environment variable means anything to CONSTANT_CASE.

Creating slugs and filenames. URLs, file names and CSS classes conventionally use kebab-case or snake_case. Converting a title directly avoids the manual find-and-replace.

Undoing caps lock. The classic case: half a paragraph typed with caps lock on. Convert to lowercase, then to sentence case, and it is fixed.

Tips for getting the result you want

Chain conversions for messy input. Text with random capitalisation — tHe QUICK brown FOX — does not convert cleanly to Title Case in one step, because the converter preserves nothing it cannot interpret. Apply lowercase first to normalise everything, then apply the case you actually want. Two clicks, reliably correct.

Use Title Case when your text has names in it. Sentence case has to lowercase the text before rebuilding it, which destroys proper nouns. If your headline is "the paris review interviews david foster wallace", sentence case gives you a lowercase Paris and a lowercase David. Title Case capitalises every significant word, which is closer to correct and leaves less to fix.

Know which minor words stay lowercase. Title Case here leaves articles, short conjunctions and short prepositions lowercase — a, an, the, and, but, or, for, in, on, at, to, of, by, with and similar — unless the word is first, last, or follows a colon. This matches the common editorial convention. Some style guides differ, most notably on prepositions of four letters or more, so check your house style if it matters.

Programming cases discard your punctuation. Converting to camelCase or snake_case strips spaces and punctuation by design, since those formats cannot contain them. Use them on short strings — a variable name, a title becoming a slug — not on whole paragraphs.

Acronyms convert correctly, but check them. getHTMLElement correctly becomes get-html-element because the converter detects the acronym boundary. Going the other way it cannot know that html should be HTML, so get-html-element becomes getHtmlElement. That is usually what you want in JavaScript, but not always.

Limits and requirements

Sentence case cannot recover proper nouns. This is inherent rather than a shortcoming of this implementation. Converting to sentence case lowercases everything, and there is no reliable way to know which lowercase words should be capitalised. Names, places, brands and days of the week will need fixing by hand. The converter restores the pronoun "I" and recognised title abbreviations, which covers the most common cases.

Abbreviation detection covers common cases, not all of them. Titles (Dr., Mrs., Prof.), business suffixes (Inc., Ltd., Corp.), months, days and common Latin abbreviations are recognised and will not be treated as sentence endings. An unusual or domain-specific abbreviation may still be misread as the end of a sentence.

Title Case follows one convention. Style guides genuinely disagree — Chicago, AP and MLA each treat prepositions slightly differently. This converter uses the widely applicable version described above. If you are writing to a specific style guide, check its rules on longer prepositions.

Non-Latin scripts. Case conversion works for any script that has upper and lower case forms, including Cyrillic and Greek. Scripts without case distinction — Chinese, Japanese, Arabic, Hebrew, Devanagari — pass through unchanged, which is correct behaviour rather than an error.

Browser support. Any modern browser from roughly the last five years, on desktop or mobile. JavaScript must be enabled. Copying uses the clipboard API, which requires a secure connection — on this site that is always the case.

Privacy: how this tool handles your text

Everything happens on your device. When you type or paste, the text is held in your browser's memory and converted by JavaScript running locally. It is never transmitted to our servers, never written to a database, never logged.

This matters because text people convert is often not public. A draft headline for an unannounced product. A list of customer names being reformatted. Variable names from a private codebase. Pasting any of those into a tool that posts to a server hands a copy to a third party whose retention policy you have not read.

You can check this rather than trusting it. Open your browser's developer tools, switch to the Network tab, and type into the box. No request carries your text, because there is nowhere for it to go. Close the tab and it is gone.