How do I convert uppercase to lowercase or lowercase to uppercase?

Paste your text and copy the lower case or UPPER CASE row. HELLO World becomes hello world in lowercase and HELLO WORLD in uppercase. Spacing and punctuation stay in place; Unicode casing can change the number of characters, as ß becomes SS when uppercased.

What is the difference between title case and proper case?

For a day in the sun, Title Case gives A Day in the Sun and Capitalized Case gives A Day In The Sun. Title Case uses the displayed fixed small-word list. Proper case here lowercases the text and capitalizes the first letter of each whitespace-separated word; it does not infer personal names.

Can I convert camelCase to snake_case and back?

Yes. XMLParser becomes xml_parser in snake case, and hello_world becomes helloWorld in camel case. Spaces, underscores, hyphens, dots and slashes split words, as do Unicode lowercase-or-number to uppercase boundaries and an acronym followed by a normal capitalized word. All-uppercase acronyms are lowercased before rebuilding. This is a text transform, not a JSON-key or source-code refactoring operation.

Can I make alternating, SpongeBob or inverse case?

The alternating row changes casing by code-point position, counting spaces and punctuation too: hello becomes hElLo. It is deterministic rather than random. Inverse swaps each letter’s case; Unicode mappings such as ß to SS mean swapping twice is not always an undo.

What does lowercase mean, and where are the A–Z pairs?

Lowercase letters are forms such as a, b and c; their uppercase partners are A, B and C. The Latin pairs are ABCDEFGHIJKLMNOPQRSTUVWXYZ and abcdefghijklmnopqrstuvwxyz. Paste a letter or an alphabet into the box to see both forms. The converter does not generate printable lessons or matching worksheets.

Does this respect accents, Greek sigma and Turkish casing?

Accented letters and scripts with case use JavaScript’s default Unicode mappings. Greek ΟΣ lowercases to ος. There is no Turkish locale selection: I lowercases to i, İ to i plus a combining dot, and i uppercases to I. Scripts without case remain unchanged. Review language-specific conventions.

Can I change case in Word, Excel or a PDF here?

For plain text, copy it from the source application, paste it here, copy a result and paste it back. This does not edit a workbook or PDF, preserve rich formatting, apply a Word shortcut or supply an Excel formula.

Conversion runs in this browser. Your draft is remembered on this device; opening a page with an example does not replace the remembered draft until you edit that example.

Case Converter

Change uppercase to lowercase, lowercase to capitals, or compare 13 text cases at once. Every result appears as you type with its own Copy button. Title Case keeps listed small words lowercase in the middle; Capitalized Case, also called proper case here, capitalizes every whitespace-separated word. Identifier styles convert separators and capital boundaries without parsing source code.

Your text

13 cases at onceNothing uploadedWorks offline

Text case examples

Each row converts the same input, hello world. Choose the output you need and copy it.

Case	Output	Typical use
Sentence case	Hello world	A sentence opening
Title Case	Hello World	Headings
Capitalized Case	Hello World	Every word starts with a capital
UPPER CASE	HELLO WORLD	All capitals
lower case	hello world	Remove capitals
camelCase	helloWorld	Variable names
PascalCase	HelloWorld	Class and component names
snake_case	hello_world	Underscore-separated names
CONSTANT_CASE	HELLO_WORLD	Constants
kebab-case	hello-world	Hyphen-separated names
dot.case	hello.world	Dotted keys
Alternating case	hElLo wOrLd	Alternating character positions
Inverse case	HELLO WORLD	Swap each letter’s case

Common questions

How do I convert uppercase to lowercase or lowercase to uppercase?: Paste your text and copy the lower case or UPPER CASE row. HELLO World becomes hello world in lowercase and HELLO WORLD in uppercase. Spacing and punctuation stay in place; Unicode casing can change the number of characters, as ß becomes SS when uppercased.
What is the difference between title case and proper case?: For a day in the sun, Title Case gives A Day in the Sun and Capitalized Case gives A Day In The Sun. Title Case uses the displayed fixed small-word list. Proper case here lowercases the text and capitalizes the first letter of each whitespace-separated word; it does not infer personal names.
Can I convert camelCase to snake_case and back?: Yes. XMLParser becomes xml_parser in snake case, and hello_world becomes helloWorld in camel case. Spaces, underscores, hyphens, dots and slashes split words, as do Unicode lowercase-or-number to uppercase boundaries and an acronym followed by a normal capitalized word. All-uppercase acronyms are lowercased before rebuilding. This is a text transform, not a JSON-key or source-code refactoring operation.
Can I make alternating, SpongeBob or inverse case?: The alternating row changes casing by code-point position, counting spaces and punctuation too: hello becomes hElLo. It is deterministic rather than random. Inverse swaps each letter’s case; Unicode mappings such as ß to SS mean swapping twice is not always an undo.
What does lowercase mean, and where are the A–Z pairs?: Lowercase letters are forms such as a, b and c; their uppercase partners are A, B and C. The Latin pairs are ABCDEFGHIJKLMNOPQRSTUVWXYZ and abcdefghijklmnopqrstuvwxyz. Paste a letter or an alphabet into the box to see both forms. The converter does not generate printable lessons or matching worksheets.
Does this respect accents, Greek sigma and Turkish casing?: Accented letters and scripts with case use JavaScript’s default Unicode mappings. Greek ΟΣ lowercases to ος. There is no Turkish locale selection: I lowercases to i, İ to i plus a combining dot, and i uppercases to I. Scripts without case remain unchanged. Review language-specific conventions.
Can I change case in Word, Excel or a PDF here?: For plain text, copy it from the source application, paste it here, copy a result and paste it back. This does not edit a workbook or PDF, preserve rich formatting, apply a Word shortcut or supply an Excel formula.
Is my text uploaded?: Conversion runs in this browser. Your draft is remembered on this device; opening a page with an example does not replace the remembered draft until you edit that example.

Uses JavaScript default Unicode casing, with no locale selector. Title and sentence rules are mechanical: they do not infer names, abbreviations or a complete editorial style guide.