Case Converter
Switch text between uppercase, lowercase, title case, and sentence case instantly. Smart title-case preserves acronyms.
Advanced — Smart title-case · Standard mode · Spacing preserved
What is Case Converter?
A case converter is an online tool that transforms text between uppercase, lowercase, title case, sentence case, and invert case. It helps writers, editors, and developers quickly fix capitalization without retyping. Whether you need to standardize headings, fix accidentally caps-locked text, or format code identifiers, a case converter saves time and reduces manual errors.
Beyond basic styles, this tool supports camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, dot.case, and path/case — ideal for variable names, file paths, and API identifiers. Smart title-case mode preserves common acronyms like API, HTML, CSS, and USA, so "the API and HTML are working" stays correct instead of becoming "The Api And Html Are Working." Line-by-line mode applies conversion to each line independently, perfect for lists, headings, or CSV columns.
Real-world use cases include formatting blog titles for consistency, converting legacy database fields to snake_case, preparing text for the Slug Generator, and fixing copy-pasted text that arrived in the wrong case. The tool runs entirely in your browser; nothing is uploaded or stored.
How to Use Case Converter
- Paste or type your text into the input area.
- Click a case button: UPPERCASE, lowercase, Title Case, Sentence case, or Invert Case.
- The converted text appears instantly in the result area below.
- Open Advanced to enable smart title-case (preserve acronyms), line-by-line mode, or punctuation spacing.
- Click Copy to copy the result to your clipboard.
Tips & Best Practices
Use Ctrl+Enter to re-apply the last conversion mode — handy when you tweak the input and want the same style again. Press Ctrl+Shift+C to copy the result without clicking, and Esc to clear both input and output. For lists of titles or headings, enable Line-by-line mode so each line is treated as its own sentence or title. When converting technical content, keep Smart title-case on to avoid breaking acronyms like JSON, REST, or GDPR.
Edge case: if your text has mixed punctuation (e.g., "word,next" without a space), enable Preserve punctuation spacing to ensure proper spacing after commas and periods. For URL slugs or filenames, pair this tool with the Slug Generator — convert to lowercase first, then generate the slug.
When to Use This Tool
Use the Case Converter when standardizing headings across a document, fixing accidentally caps-locked paragraphs, formatting variable names for code (camelCase, snake_case), preparing titles for URLs or filenames, or converting CSV columns in bulk. For comparing text before and after changes, use the Diff / Text Compare tool. For counting words or characters, try the Word Counter.
Frequently Asked Questions
What is title case?
Title case capitalizes the first letter of each word. Smart title-case also preserves acronyms like API, HTML, and USA.
What is sentence case?
Sentence case capitalizes only the first letter of the first word and proper nouns, like a normal sentence.
What does invert case do?
Invert case flips each character: uppercase becomes lowercase and lowercase becomes uppercase.
Is my text stored or sent anywhere?
No. The case converter runs entirely in your browser. Your text is never uploaded or stored.
Can I convert headings or titles?
Yes. Paste your text, click UPPERCASE, lowercase, Title Case, or Sentence case, then copy the result. For URL slugs, try our Slug Generator.
What is line-by-line mode?
Line-by-line mode applies the conversion to each line independently, treating each line as a separate sentence or title. Useful for converting lists or headings.