Text Case Converter

Convert text casing instantly with automatic proper-noun recognition, smart capitalization rules, and custom dictionary overrides.

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Transformations

Click any button to transform text

Smart Proper Noun Protection

Preserves exact canonical casing for words like iPhone, YouTube, ChatGPT, and Next.js, even after transformations.

100% Client-Side Privacy

All conversions run purely in your local browser JavaScript engine. No text, tokens, or personal data ever leave your device.

Real-Time Stats & Utilities

Includes character, word, sentence, and line counts, instant undo history, whitespace cleaner, and TXT file export.

Supported Casing Styles & Definitions

Sentence case

Capitalizes the initial letter of every sentence while keeping subsequent words lowercase.

Example: The quick brown fox jumps.

Title Case

Capitalizes major words while keeping articles, conjunctions, and prepositions lowercase.

Example: The Art of Computer Programming

UPPER CASE

Transforms all alphabetic characters in the text to capital letters.

Example: ALL UPPERCASE TEXT

lower case

Transforms all alphabetic characters in the document to lowercase.

Example: all lowercase text

Capitalized Case

Capitalizes the first character of every single word in the text.

Example: Every Single Word Capitalized

aLtErNaTiNg cAsE

Alternates casing between lowercase and uppercase across letter positions.

Example: aLtErNaTiNg cAsE tExT

Frequently Asked Questions

Is my text sent to any server or API?

No. ConvertCase is 100% browser-native. All parsing, transformation, and regex matching occur strictly inside your local browser tab.

Can I add custom proper nouns or brand names?

Yes. Click the Settings icon in the top header to enter your custom brand names and terms. Your custom dictionary rules will automatically override standard transformations.