Case Converter
A case converter takes one block of text and instantly generates it in every common capitalization style, including UPPER CASE, lower case, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case, and CONSTANT_CASE. Type or paste your text into the box, click Convert Case, and the tool reads each word boundary in your input, whether it is marked by a space, a _ character, a hyphen, or an internal capital letter, then rebuilds the phrase using the capitalization and separator rules of every supported format at once. Writers use it to fix text pasted from a spreadsheet that landed in all caps, developers use it to turn a plain phrase into a valid variable name, and editors use it to standardize headline capitalization across a batch of articles. Everything runs in your browser, so nothing you type is uploaded or stored anywhere.
Quick answer
Converts text to upper, lower, title, sentence, camel, pascal, snake, kebab, and constant case in a single pass.
What this tells you
- •Converts text to upper, lower, title, sentence, camel, pascal, snake, kebab, and constant case in a single pass.
- •Word normalization splits your input on spaces, _ characters, hyphens, and camelCase boundaries before rebuilding each format.
- •Title Case and Pascal Case capitalize the first letter of every detected word and lowercase the rest.
- •camelCase keeps the first word lowercase and capitalizes every word after it, with no separators between words.
- •snake_case, kebab-case, and CONSTANT_CASE join words with a _ character, a hyphen, or uppercase words joined by _ instead of spaces.
- •Outputs update instantly and are generated entirely client-side from the text you provide, so nothing leaves your browser.
How to Use
- 1Paste or type the text you want to convert into the input box. Full sentences, short phrases, and single words all work.
- 2Click Convert Case to generate every supported case format from that one input.
- 3Scan the results panel for the format you need, such as camelCase for a JavaScript variable or Title Case for a headline.
- 4Copy the output format you need directly from the results, ready to paste into your code editor, CMS, or document.
- 5If your source text already mixes styles, such as a snake_case variable name you want turned into a readable title, run it through once and confirm the split points match what you expect before using the result.
How It Works
Formula
Word normalization -> case-specific transformations (capitalization + separators)The tool first tokenizes your text into individual words. It inserts a space before every lowercase-to-uppercase transition (so 'helloWorld' becomes 'hello World'), then treats _ characters and hyphens as word breaks and collapses everything into a clean list of lowercase words. From that shared word list, each output format applies its own two rules: a capitalization rule (leave lowercase, capitalize first letter, or uppercase everything) and a separator rule (space, no separator, _ character, hyphen, or _ character with uppercase). Upper case and lower case skip tokenization entirely and just change every character in the original string. Sentence case lowercases the whole string, then capitalizes the first letter of the string and the first letter after any period, question mark, or exclamation point followed by whitespace.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Convert a phrase to programming and writing cases
The tool splits the phrase into three words (hello, world, test) using the spaces as boundaries. camelCase keeps the first word lowercase and capitalizes the rest with no separators, snake_case joins all three lowercase words with _ characters, and Title Case capitalizes the first letter of each word while keeping the spaces.
Normalize a snake_case variable name into a readable title
The _ characters in user_first_name are detected as word boundaries, so the tool splits it into user, first, and name before rebuilding each format. Title Case turns it into a readable label for a form or report, while PascalCase produces a class-name-style identifier and kebab-case produces a URL-friendly slug.
Convert a camelCase identifier into CONSTANT_CASE
Because maxRetryCount has no spaces, the tool detects word breaks at each lowercase-to-uppercase transition, splitting it into max, retry, and count. CONSTANT_CASE uppercases every word and joins them with _ characters, which matches the naming convention many languages use for constant values.
Clean up text pasted from an all-caps spreadsheet cell
Spreadsheet exports and legacy databases often store labels in all caps. Title Case restores each word's capital first letter for a report heading, while lower case gives a clean, fully lowercase version useful for search matching or slug generation before further edits.
Turn a sentence into a kebab-case URL slug
The tool splits the sentence into words on the spaces (Best, Budget, Laptops, 2026), lowercases each one, and joins them with hyphens for kebab-case or _ characters for snake_case. Kebab-case is the format most CMS platforms and web frameworks expect for URL slugs.
Turn a draft headline into a URL slug and a title
Dana drafts a blog post headline in sentence case and needs two more versions before publishing. The converter splits the 9 words on the spaces. kebab-case lowercases every word and joins them with hyphens, which gives the slug best-time-to-buy-a-used-car-in-2026, the hyphenated form Google Search Central recommends for URLs. Title Case capitalizes the first letter of every word, including a, to, and in, so the output is Best Time To Buy A Used Car In 2026. AP and Chicago headline styles would both keep a, to, and in lowercase here, so Dana lowercases those three by hand before the title goes live.
Case styles and where each one is expected
Every style the converter produces, shown for the phrase max retry count, with the convention or style guide that calls for it.
| Style | Output for max retry count | Where it is expected | Convention |
|---|---|---|---|
| lowercase | max retry count | Text you normalize before matching, sorting, or deduplicating | General practice, no single standard |
| UPPERCASE | MAX RETRY COUNT | Acronyms such as NASA, warning labels, some print headings | General practice |
| Sentence case | Max retry count | Headings and interface text in sentence-case house styles | The Google developer documentation style guide uses sentence case for headings |
| Title Case | Max Retry Count | Book, article, and headline titles | AP and Chicago both use it but differ on which short words stay lowercase. This tool capitalizes every word. |
| camelCase | maxRetryCount | Variables and functions in JavaScript and Java | Google JavaScript Style Guide (lowerCamelCase for variables and functions) |
| PascalCase | MaxRetryCount | Class and type names | PEP 8 (CapWords for Python classes) and the Google JavaScript Style Guide (UpperCamelCase for classes) |
| snake_case | max_retry_count | Python functions and variables | PEP 8 (lowercase with underscores for functions and variables) |
| kebab-case | max-retry-count | URL slugs, CSS class names, HTML attributes | Google Search Central URL structure guidance recommends hyphens rather than underscores in URLs |
| CONSTANT_CASE | MAX_RETRY_COUNT | Constants and environment variables | PEP 8 (UPPER_CASE_WITH_UNDERSCORES for constants) and the Google JavaScript Style Guide (CONSTANT_CASE) |
Outputs computed with this converter. Conventions from PEP 8 (Python), the Google JavaScript Style Guide, and Google Search Central URL structure guidance. Title Case here capitalizes the first letter of every word and lowercases the rest, with no small-word list, so AP or Chicago headline style will differ for words like a, to, and in.
Which case style goes where
Programming conventions are the most settled. PEP 8, the Python style guide, asks for lowercase with underscores for functions and variables, uppercase with underscores for constants, and CapWords for class names. The Google JavaScript Style Guide asks for lowerCamelCase for variables and functions, UpperCamelCase for classes, and CONSTANT_CASE for constants. Run a plain phrase through the converter and copy the row that matches the language you are writing in.
URLs and headlines follow different rules. Google Search Central's URL structure guidance recommends hyphens rather than underscores to separate words in a URL, which is exactly what kebab-case produces. For headlines, sentence case and Title Case are both common. AP and Chicago both lowercase some short words in a title, but they do not agree on which ones, so a Title Case output still needs a pass against whichever style guide your publication follows.
The converter's Title Case rule is simple on purpose. It capitalizes the first letter of every detected word and lowercases the rest, with no list of small words to skip. That means a, an, the, to, of, and in all get a capital letter, and words with their own capitalization lose it, so NASA becomes Nasa and iPhone splits into I Phone because the internal capital reads as a word boundary. Treat the output as a first pass, then fix articles, prepositions, acronyms, and brand names by hand.
Uppercase and lowercase use the browser's default Unicode case mapping, which has documented exceptions in the Unicode Standard's SpecialCasing data. The German sharp s has no single uppercase letter, so straße uppercases to STRASSE and does not return to its original spelling when lowercased again. Turkish and Azeri use a dotless i and a dotted capital I, and those locale-specific mappings are not applied here, so the converter follows the default rule where i uppercases to I. Check text in those languages before publishing.
Common mistakes
- Assuming the converter recognizes acronyms and proper nouns. Words like 'USA', 'NASA', or 'McDonald's get flattened into the target case rules just like any other word, so you often need to fix a handful of characters by hand after converting.
- Running mixed-format text through the tool without checking the split points. Text that already combines camelCase and snake_case, such as 'userID_value', can split in a way you did not expect, so it is worth scanning the tokenized result before copying it into code.
- Using Sentence case on text full of abbreviations. Periods after abbreviations like 'e.g.' or 'Inc.' are indistinguishable from real sentence endings to the tool, so the word right after an abbreviation can get an unwanted capital letter.
- Pasting code snippets that include punctuation, symbols, or multiple identifiers at once. The tool tokenizes on spaces, hyphens, _ characters, and camelCase boundaries, not on commas, parentheses, or semicolons, so converting a full line of code usually produces messier results than converting one identifier at a time.
- Forgetting that upper case and lower case do not use word tokenization at all. They change every character in your original string directly, so any typos, extra spaces, or inconsistent spacing in your input carry straight through to the output.
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