Case Converter

Caps lock accidents, pasted ALL CAPS emails, and mismatched headline styles burn time before the real editing begins. This case converter changes letter casing across a block of text so you can normalize drafts, CMS fields, and checklist lines into UPPERCASE, lowercase, Title Case, or Sentence case in one pass. It is a typography helper, not a full style-guide engine: brand spellings, product names, and acronyms still need a human pass. Processing stays on your device, which matters when the paste contains unpublished copy. Choose the case your template expects, review exceptions, then copy the result into the document that will actually publish.

Informational only; verify critical results independently.

How to use

  1. Paste or type the text whose letter casing you want to normalize.
  2. Pick UPPERCASE for shouty constants and mock legal lines, lowercase for slug prep, Title Case for many English headlines, or Sentence case for readable prose.
  3. Scan proper nouns, product names, and acronyms after Title Case or Sentence case—automatic rules cannot know “iPhone” or “NASA.”
  4. Copy the transformed text into your CMS, design brief, spreadsheet, or code comment.
  5. Re-run with a different case if your house style prefers sentence case headlines over title case.
  6. Keep punctuation and spacing intact; only letter case should change for a clean before/after compare.
  7. For mixed blocks, convert the whole paste once, then hand-fix subsections rather than chaining five conflicting modes.
  8. Clear sensitive drafts from shared machines after you copy the result, even though processing never leaves the browser.

Examples

  • ALL CAPS memo → Sentence case for a readable internal update.
  • “best coffee shops in lisbon” → Title Case for a blog headline draft.
  • Mixed CapsLock paragraph → lowercase, then Sentence case for recovery.
  • API constant label → UPPERCASE for a mock config screenshot.
  • CSV column headers → Title Case before importing into a report.
  • URL path fragment “Summer-Sale-2026” → lowercase summer-sale-2026 prep before slugging.
  • Bullet list that arrived in TITLE CASE → Sentence case for a product brief.
  • Disclaimer line → UPPERCASE when a mock requires caps-style emphasis.
  • “mcdonald’s vs McDonald’s” → manual fix after Title Case, because automatic tools may mangle apostrophe brands.

FAQ

Does punctuation and spacing survive conversion?
Yes. Spaces, digits, and common punctuation remain. Only alphabetic casing changes. If something disappears, you likely selected a different transform or trimmed the paste yourself.
How does Title Case decide which words to capitalize?
Implementations usually capitalize the first letter of each whitespace-separated token. They do not encode Chicago Manual exceptions for short prepositions. Expect to demote “Of,” “And,” or “The” mid-title by hand when your style guide requires it.
What is Sentence case compared with Title Case?
Sentence case capitalizes the start of the string (and often the start of each sentence) while leaving other words lowercase. Title Case capitalizes most words. News sites and many European brand voices prefer sentence case headlines.
Will accented letters and non-Latin scripts convert correctly?
Modern browsers apply Unicode case mapping. Latin letters with diacritics generally round-trip. Scripts without case distinction are unchanged. Always spot-check languages you publish in.
Why does this differ from Excel PROPER or Word’s Change Case?
Each product splits words differently around hyphens, apostrophes, and small words. Pick one behavior for a project and stay consistent rather than mixing tools mid-document.
Should I run case conversion on HTML or Markdown source?
Prefer plain text excerpts. Running Title Case over raw HTML can alter tag names or attributes if letters sit inside markup. Convert visible copy, then paste back into structured fields.
Can case conversion fix brand spelling like iPhone?
No automatic mode knows proprietary mid-word capitals. Convert the surrounding sentence, then restore brand spellings from an official style list.
Is UPPERCASE the same as small caps in design tools?
No. UPPERCASE changes character codes to capital letters. Small caps are a typographic presentation that may keep lowercase codes. Design systems should treat them separately.
How should I handle acronyms inside Title Case?
After conversion, force acronyms like “API,” “GDP,” or “HTML” back to their conventional form. Automatic title casers often leave “Api” or “Html,” which looks unfinished in technical headlines.
Does lowercase help before creating a URL slug?
Often yes. Lowercasing first removes accidental CapsLock noise so a slugify step produces stable kebab-case. Still verify uniqueness in your CMS.
What about Turkish dotted and dotless I?
Locale-sensitive casing can surprise you: capital “I” may not map the way English speakers expect. If you publish Turkish copy, verify casing with a locale-aware editor for final proofs.
Is my text uploaded anywhere?
No. Transformation runs locally in the browser. That keeps unpublished manuscripts and client drafts off remote servers during a simple case fix.

Formula / Method

Uppercase and lowercase map each letter via Unicode case folding rules exposed by the browser. Title Case typically splits on whitespace (and sometimes punctuation) and uppercases the first character of each token while lowercasing the remainder. Sentence case lowercases the block, then uppercases the first letter of the string and of sentence starts after terminal punctuation. Example: “hello WORLD” → UPPERCASE “HELLO WORLD”; Title Case often becomes “Hello World”; Sentence case becomes “Hello world.” No semantic rewrite occurs—only code-point casing changes.

Assumptions & Limitations

Does not implement a full editorial style guide, brand dictionary, or grammar engine. Hyphenated compounds, particles in multi-word names, and language-specific casing rules may need manual correction. Not a substitute for legal-document capitalization requirements. Extremely large pastes are limited by browser memory. Privacy assumes you use a trusted device; local processing does not encrypt a screen shared with others.

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Last updated: 2026-07-28

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