Case Converter

About the Case Converter

Text case sounds trivial until you have retyped a 300-word paragraph because it was pasted in capitals, or hand-converted a phrase into a variable name for the fifth time. A case converter does these rewrites in one step. This page takes whatever you type and shows nine versions at once: UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, and CONSTANT_CASE. Each version has its own Copy button, so you pick the one you need and move on.

The nine styles fall into two families. The first four are prose styles that keep your spaces and punctuation and only change which letters are capitalized. The last five are programmer styles, which throw away spaces and punctuation, split the text into words, and glue those words back together with a convention that identifiers can legally contain: capital letters, underscores, or hyphens. Those conventions are not arbitrary. Languages, frameworks, file systems, and URLs each have preferred styles, and following them keeps code and filenames consistent.

Writers, students, marketers, developers, and data cleaners all end up here for different reasons. A shouting email subject needs to become Sentence case, a spreadsheet column header needs to become snake_case for a database import, and a blog headline needs Title Case. The converter works on letters and digits in the basic English alphabet, and the sections below spell out where its rules are simple on purpose, such as acronyms, contractions, and accented characters, so you know what to check before you copy.

When to Use It

How to Use It, Step by Step

1. Click into the box labeled "Your text". It starts with the sample sentence "The quick brown fox", so select all of it first and then type or paste your own text over it.
2. Paste or type the text you want to convert. It can be a single word, a phrase, or several sentences; line breaks are allowed, and the converted rows update on every keystroke.
3. Scan the nine rows below the box: UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, and CONSTANT_CASE. Your original text in the box is never modified.
4. Check the row you need for anything surprising, especially acronyms, contractions, or accented letters, because those are handled by simple rules described in this page.
5. Long results are cut off with an ellipsis in the row. Hover over the text to see the full value in a tooltip; the Copy button always copies the complete string, not the shortened view.
6. Press the Copy button at the right of the row you want. It briefly changes to "Copied" to confirm. If your browser blocks clipboard access, select the text in the row and copy it manually.
7. Paste the result where you need it, then proofread proper nouns, acronyms, and the word I, which the prose styles do not recognize.

Understanding Your Results

The four prose rows keep the shape of your text. UPPERCASE and lowercase simply change every letter. Title Case capitalizes the first letter of every word and lowercases the rest, with no list of small words, so "of" and "the" are capitalized too. Sentence case lowercases everything and then capitalizes the first letter of the text and the first letter after each period, exclamation mark, or question mark. A colon does not start a new sentence, so the word after a colon stays lowercase.

The five programmer rows discard everything except letters and digits. The text is cut into runs of A-Z, a-z, and 0-9, and those runs become the words. Anything else, including spaces, apostrophes, hyphens, underscores, punctuation, and accented letters, acts as a separator and is dropped. That is why "version 2.1" becomes version_2_1: the period splits the digits into separate words. The converter also does not detect word boundaries inside an existing camelCase word, so getHTTPResponse is treated as one word.

As a sanity check, count the words you expect and compare them with the underscores or hyphens in the snake_case or kebab-case row; there should be one fewer separator than words. If the count is off, look for apostrophes, accented letters, or digits that split a word you wanted whole, fix those in the input box, and the rows update immediately.

More Worked Examples

Tips for Better Results

• Add spaces between words before converting an existing camelCase or PascalCase name. Typing "get HTTP response" gives you get_http_response in snake_case, whereas getHTTPResponse stays one word.
• Replace accented letters with plain ones, such as cafe for café, before generating programmer styles or Title Case. The tool treats an accented letter as a separator, which splits and drops pieces of the word.
• For headlines in AP, Chicago, or APA style, use Title Case as a starting point and then lowercase short articles, conjunctions, and prepositions such as of, the, and in by hand.
• Use kebab-case for URLs and CSS classes, snake_case for database columns and Python names, camelCase for JavaScript variables, PascalCase for class and component names, and CONSTANT_CASE for fixed values in most languages.
• Digits count as word characters, so "2nd place" becomes 2nd_place and "version 2.1" becomes version_2_1. If you want 2.1 kept together in an identifier, edit the copied result by hand.
• After converting a long paragraph, skim the Title Case and Sentence case results for acronyms, since NASA becomes Nasa and an initialism you retype needs its capitals restored.

Common Mistakes to Avoid

• Expecting Title Case to leave acronyms alone. Every word is lowercased after its first letter, so USA becomes Usa. Retype acronyms after copying.
• Pasting an apostrophe-rich sentence into a programmer style. Contractions split into pieces, so it's turns into it_s. Remove the apostrophes or expand the contraction first.
• Treating Sentence case as grammar-aware. It does not know proper nouns, the pronoun I, or abbreviations that end with a period, so "Dr. smith" becomes "Dr. Smith" and "e.g. this" becomes "E.G. This".
• Using a programmer row for text that has accented characters or non-Latin letters. The converter keeps only A-Z, a-z, and 0-9, so such characters vanish and the result may be shorter than you expect.
• Assuming the original box has been changed. The tool never overwrites your input, so if you want to reuse the converted text, press the Copy button and paste it elsewhere.

Assumptions and Limits

• Word detection for the programmer styles uses plain ASCII letters and digits only. Text in other alphabets, or with accents, will be split or dropped, so this tool is reliable mainly for English text.
• Title Case here is mechanical: every word is capitalized, with no style-guide exceptions. It is a first draft for headlines, not a substitute for editorial rules.
• Sentence case recognizes the start of the text and the characters . ! ? as sentence boundaries. It cannot recognize names, abbreviations, or quoted sentences, so proofread the result before sending.
• Everything runs locally in your browser, so there is no length limit imposed by a server; very large documents are limited only by your device.

Key Terms

camelCase

A naming style that joins words with no separator and capitalizes every word except the first, such as maxRetryCount. It is the usual style for variables and functions in JavaScript and Java.

PascalCase

The same as camelCase, but the first word is also capitalized, as in MaxRetryCount. It is commonly used for class names and UI component names.

snake_case

A style that writes words in lowercase and joins them with underscores, such as max_retry_count. Python and many database schemas prefer it.

kebab-case

Lowercase words joined with hyphens, like max-retry-count. It is common in URLs, CSS class names, and filenames, but most programming languages cannot use it for variable names.

CONSTANT_CASE

Uppercase words joined with underscores, such as MAX_RETRY_COUNT. It is the conventional way to name fixed values and environment variables.