🔡 Case Converter

What is the Case Converter?

Letter case is the difference between capital letters (A, B, C) and small letters (a, b, c). Most writing mixes the two by convention: a sentence starts with a capital, proper nouns are capitalised, and the rest is lowercase. A case converter automates the tedious job of changing that convention across a whole block of text, which is far faster and more reliable than retyping or holding Shift while you fix each word by hand.

The styles fall into two groups. Reading styles are meant for human text: UPPERCASE shouts, lowercase is quiet and informal, Title Case suits headings, and Sentence case is the normal flow of prose with only the first word and proper nouns capitalised. Programmer styles join words together without spaces because most languages do not allow spaces in names: camelCase (firstNameField), snake_case (first_name_field), and kebab-case (first-name-field) are the three you meet most often in code, file names, URLs, and database columns.

Under the hood, converting between these styles means deciding where one word ends and the next begins. For spaced text that is easy. For programmer styles the converter also has to split existing camelCase boundaries (the capital M in fileName marks a new word) and treat punctuation, spaces, and underscores as separators. Once the words are identified, each style simply rejoins them with its own rule: a separator character for snake and kebab, or capitalised first letters with no gaps for camel.

When to use it

• Fixing a heading or title that was typed in all caps or all lowercase so it reads as proper Title Case.
• Turning a label like "First Name" into a code-friendly variable such as firstName, first_name, or first-name.
• Cleaning up text pasted from a spreadsheet or PDF where the capitalisation came out wrong.
• Creating a URL slug or file name from a page title by converting it to kebab-case.

How to use the Case Converter

1. Type or paste your text into the input box.
2. Click the case you want: UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case, or kebab-case.
3. Read the converted text in the result box below.
4. Click Copy to send the result to your clipboard, then paste it wherever you need it.

Formula & method

Worked examples

How each case style rewrites the phrase "Hello World Example"

Common mistakes to avoid

• Confusing Title Case with capitalising every letter. Title Case capitalises only the first letter of each word (Hello World). Putting every letter in capitals is UPPERCASE (HELLO WORLD), which reads as shouting and is harder to scan.
• Expecting Title Case to skip small words. Strict editorial title case leaves short words like "and", "of", or "the" lowercase. This tool capitalises the first letter of every word, so always proofread a headline if you follow a specific style guide.
• Using spaces in code names. Programming languages do not allow spaces inside variable or file names. That is the whole reason camelCase, snake_case, and kebab-case exist, so pick one of those rather than leaving spaces in.
• Mixing snake_case and kebab-case in code. Underscores and hyphens are not interchangeable. Many languages treat a hyphen as a minus sign, so kebab-case is usually safe only in URLs, CSS, and file names, not in variable names.

Glossary

Letter case

Whether a letter is written as a capital (uppercase) or small (lowercase) form, such as A versus a.

Title Case

A style where the first letter of each word is capitalised, commonly used for headings and titles.

Sentence case

Normal prose capitalisation: only the first word of a sentence and proper nouns start with a capital letter.

camelCase

A naming style where words are joined with no spaces, the first word is lowercase, and each later word starts with a capital, like firstName.

snake_case

A naming style where lowercase words are joined by underscores, like first_name.

kebab-case

A naming style where lowercase words are joined by hyphens, like first-name, common in URLs and CSS.

Frequently asked questions