Case Converter

What does the Case Converter do?

This free online case converter changes the capitalisation of your text. Paste any block of text, pick a case style from the dropdown, and the tool instantly converts it to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case, kebab-case, and ten other common formats.

Unlike simple tools that only handle one or two conversions, this case converter covers everything you need in one place — from every-day writing tasks like fixing headings and titles, to developer tasks like converting variable names between camelCase and snake_case.

Everything runs locally in your browser using JavaScript. The text you paste never leaves your device — there is no server processing, no logging, and no data storage. Close the tab and it's gone.

How to use the Case Converter

1. Paste or type your text: Drop any text into the input box on the left. It can be a heading, a paragraph, a variable name, a URL slug, or a full document.
2. Pick a case style from the dropdown: The Case Style dropdown groups all 15 styles into 4 categories — Writing, Fun / Utility, Programming, and Other. Pick the one you need and the conversion happens instantly.
3. Review the result: The output panel shows the converted text along with live word, character, and line counts. You can switch between case styles without retyping.
4. Copy or download: Use the Copy Output button to grab the converted text, or download it as a .txt file.

Why use this Case Converter?

All 15 case styles explained

Title Case vs Sentence case — which should you use?

These two styles look similar but follow different rules, and choosing the wrong one for a heading or title can look unprofessional. Here's the short version:

• Sentence case capitalises only the first letter of the first word, plus proper nouns. It's the standard for most modern prose, web copy, captions, subheadings, and body text. Example: The quick brown fox jumps over the lazy dog.
• Title Case capitalises the first letter of every major word — nouns, verbs, adjectives, adverbs — and leaves short articles, conjunctions, and prepositions lowercase (unless they start or end the title). It's the standard for book titles, article titles, headlines, and blog post titles. Example: The Quick Brown Fox Jumps Over the Lazy Dog.

Style guides disagree on exactly which short words to leave lowercase. Most follow the rule: a, an, and, as, at, but, by, for, in, nor, of, on, or, per, the, to, up, via, and similar short words stay lowercase unless they are the first or last word. This tool follows that convention.

Programming case conventions at a glance

If you write code in more than one language, this table is a handy cheat-sheet for which case style belongs where:

The exact convention varies by project and style guide, but the table above reflects the most widely used defaults in each ecosystem.

Common use cases for the Case Converter

1. Fixing accidentally-caps-locked text

If you accidentally type with Caps Lock on, paste the text into this tool and pick lowercase or Sentence case to fix it in one click. No need to retype anything.

2. Formatting headings and titles

Copy a headline, pick Title Case, and paste it back. This is especially useful when you need consistent title formatting across a document, or when you're preparing blog posts and article headers.

3. Converting between programming naming conventions

Got a variable in snake_case that needs to be camelCase for JavaScript? Paste it and pick the target style. The tool handles multi-word conversions correctly, including handling existing separators.

4. Creating URL slugs

Copy a heading like "How to Write a Blog Post in 2025" and convert it to kebab-case to get how-to-write-a-blog-post-in-2025 — ready to paste into a URL field.

5. Standardising data before import

If you're importing a list of names, tags, or categories into a system that expects a specific case format, run everything through this tool first. It avoids manual retyping and catches mistakes.

6. Preparing social media captions

Use Alternating Case (sPoNgEbOb case) for meme captions, UPPERCASE for emphasis, or Title Case for polished headlines. All in one click.

7. Cleaning up imported CSV / Excel data

Data exported from spreadsheets often has inconsistent capitalisation. Paste it in, convert to Title Case or UPPERCASE, and re-import to get a clean list.

Tips and best practices

• Watch proper nouns in Sentence case. This tool does not detect proper nouns, so converting everything to Sentence case will lowercase names like London or iPhone. Check the output and fix names manually.
• Title Case short words. Short prepositions and articles stay lowercase in Title Case (per most style guides), but the first and last words of the title are always capitalised.
• Acronyms in Title Case. Words that are already fully uppercase (like NASA or SQL) are kept as-is.
• Hyphenated words. In Title Case, hyphenated words like state-of-the-art are handled so that only the first part is capitalised, matching most style guides.
• Mixed-case inputs. If your input has unusual casing like iPhone or eBay, the converter will treat them as normal words. Review the output if this matters.
• Non-Latin scripts. CJK characters and other scripts without case have no case to convert, so they pass through unchanged. Cyrillic and Greek are handled correctly.
• Copy vs. download. If you need to paste the result somewhere else, use Copy. If you want to keep it as a file, use Download.

Related tools you might need

• Text Cleaner — clean up messy text before or after case conversion.
• Word Counter — count words and characters in your converted text.
• Title Case Converter — dedicated title case tool with style guide options.
• Uppercase Converter — dedicated uppercase tool.
• Lowercase Converter — dedicated lowercase tool.
• Capitalize Words — dedicated tool for capitalising each word.
• Toggle Case Converter — dedicated toggle case tool.
• Fancy Text Generator — Unicode-styled text for social media.
• Remove Extra Spaces — tidy spacing after conversion.

Privacy, accuracy, and limits

Privacy: Nothing you paste into this case converter is sent to a server. The whole conversion engine is a JavaScript function that runs entirely in your browser tab. There is no upload, no queue, no analytics event that includes your text, and no server-side log.

Accuracy: The tool follows standard rules for each case style and matches how most style guides and programming conventions handle capitalisation. Some edge cases — Turkish dotted/dotless I, unusual acronyms, proper nouns in Sentence case — may need a manual review.

Limits: There is no hard limit on input size. Because everything happens in-browser, the practical limit is your device's memory. Text of several megabytes processes in well under a second on a modern browser.

Frequently asked questions