Deep Dive: Case Converter
Case conversion uses JavaScript's String.toUpperCase() and String.toLowerCase() methods, which apply Unicode case mapping rules—not just ASCII A-Z. Title case capitalizes the first letter of each word (split on whitespace), though proper title case in English has exceptions (don't capitalize 'and', 'the', etc.). Sentence case capitalizes only the first letter after periods. camelCase removes spaces and capitalizes word boundaries; snake_case and kebab-case insert underscores or hyphens. Some Unicode characters have no uppercase equivalent (ẛạ), and Turkish i/İ mapping differs from English. The tool processes everything client-side, useful for formatting titles, SQL identifiers, or fixing Caps Lock mistakes.
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Privacy Architecture
This tool uses client-side WebAssembly to ensure your data never touches a server. Secure, fast, and privacy-focused by design.
Core Capabilities
- Convert to UPPERCASE
- Convert to lowercase
- Convert to Title Case (Capitalize Words)
- Convert to Sentence case
- tOGGLE cASE (Invert Case)
- Word and character count
- One-click copy
- Works offline
Why It Matters
- Time Saver: Fix capitalization errors without retyping.
- Accuracy: Ensure consistent formatting for titles and headings.
- Ease of Use: Simple buttons for every transformation.
- Privacy: Your text stays in your browser.
- Free: Unlimited use for everyone.
Quick Start Guide
Type or paste your text into the box.
Click the button for the format you want (e.g., 'UPPERCASE').
The text will instantly transform.
Click 'Copy' to save the result to your clipboard.
Use 'Clear' to start with new text.
Usage Examples
Fix Caps Lock Accidents
Scenario 01Typed with CAPS LOCK on by mistake
hELLO wORLD tHIS IS A TEST
hello world this is a test (lowercase) or Hello World This Is A Test (Title Case)
Format Blog Titles
Scenario 02Make your headings look professional
how to bake the perfect chocolate cake
How to Bake the Perfect Chocolate Cake
Convert to Variable Names
Scenario 03Turn phrases into code-friendly formats
User Profile Settings
userProfileSettings (camelCase) or user_profile_settings (snake_case)
Common Scenarios
Fixing CAPS LOCK Emails
Accidentally wrote an whole email in caps!
Coding Variable Names
Convert phrases to proper code naming conventions.
Formatting Headlines
Make blog titles and headings look polished.
Cleaning Imported Data
Fix inconsistent text from spreadsheets or databases.
Questions?
Technical Architecture
Case Conversion Types Explained
**UPPERCASE**: ALL LETTERS CAPITALIZED Use for: Emphasis, acronyms, shouting (jk, don't shout) **lowercase**: all letters small Use for: URLs, email addresses, casual text **Title Case**: First Letter Of Each Word Capitalized Use for: Headlines, book titles, proper titles **Sentence case**: Only first letter capitalized. Use for: Regular sentences, standard writing **camelCase**: firstWordLowercaseRestCapitalized Use for: JavaScript, Java variable names **snake_case**: words_separated_by_underscores Use for: Python, Ruby variable names **PascalCase**: EachWordCapitalized (like camelCase but first word too) Use for: Class names in most languages
Title Case Rules (AP Style)
Capitalize: - First and last words (always) - Nouns, pronouns, verbs, adjectives, adverbs - Words 4+ letters Don't capitalize: - Articles: a, an, the - Short prepositions: of, to, in, for - Conjunctions: and, but, or **Exception**: Capitalize if first/last word! Example: 'The Art of War' vs 'War of the Worlds' Note: Different style guides (AP, Chicago, APA) have slightly different rules. Our tool follows common web conventions.
Unicode and Case Conversion
Modern text includes more than A-Z: **Works perfectly**: - Accented letters: café → CAFÉ or Café - German: München → MÜNCHEN - Spanish: niño → NIÑO - French: français → FRANÇAIS **Limitations**: - Non-Latin scripts (中文, العربية) unchanged - Emoji stay the same (they don't have case!) - Symbols and numbers unaffected The tool uses JavaScript's built-in case conversion which follows Unicode standards.
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Related Articles
Learn more about this tool and related topics in our blog.
Essential Text Tools Every Writer Needs in Their Toolkit
From word counters to case converters, discover the essential text tools that help you write faster without sacrificing privacy.
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Privacy isn't a perk, it's a requirement. See why top developers are ditching cloud converters for local-first browser utilities.