Case Converter

The Case Converter is a free online tool that lets you change uppercase to lowercase, lowercase to uppercase, Title Case, Sentence case and more — with one click. Paste a title, paragraph, or an entire document, pick a transformation, and copy the result.

What does the Case Converter do?

Instant case conversion

The converter takes the text from the input box and applies the chosen transformation. The result updates live. You can copy it with one click or download as a .txt file.

Basic transformations

The main transformations correspond to common writing and publishing styles. Here’s how each looks when applied to the same sample sentence:

Capitalized Case vs. Title Case

These two transformations look similar but behave differently. Capitalized Case capitalizes the first letter of every word, including short ones (“a”, “an”, “the”). Title Case in Smart mode follows editorial rules: short conjunctions and prepositions are left lowercase unless they're the first or last word — this is the style used in most English-language publications for headlines.

Advanced transformations

In addition to the basic options, the tool includes developer formats (camelCase, PascalCase, snake_case, kebab-case, slug URL), text cleaning operations (trim, sorting, remove duplicates and diacritics), and Unicode stylizations (𝐛𝐨𝐥𝐝, 𝑖𝑡𝑎𝑙𝑖𝑐, 𝒮𝒸𝓇𝒾𝓅𝓉, Sᴍᴀʟʟ Cᴀᴘs). Advanced transformations are available under a collapsible section.

Language rules

Case conversion isn’t always a simple A → a mapping. A few well-known cases:

• Turkish: uppercase I → ı (dotless) and lowercase i → İ (dotted).
• German: ß becomes SS (traditionally) or ẞ (uppercase sharp s, standardized in 2017).
• Dutch: Digraph ij is traditionally written as IJ (e.g., IJsselmeer).
• Polish, Czech, Hungarian: Diacritics are preserved (ą ↔ Ą, ř ↔ Ř, ő ↔ Ő).

Select the appropriate language from the Language Rules list to get results closest to native conventions.

Proper name protection

When using Sentence case or Title Case, brand names and acronyms would normally lose their distinctive capitalization. The Protect proper names option uses a built-in dictionary of about 250 common exceptions — tech brands, acronyms (HTML, CSS, JSON), country and city names, days and months — and restores their canonical form. Names outside the dictionary are handled using default rules.

How does the converter help writers and SEO specialists?

Consistent headings and meta tags

Different publications follow different rules: AP Stylebook and BBC News use Sentence case, Chicago Manual of Style and APA use Title Case, Microsoft recommends Sentence case for UI. The tool handles the mechanical part — mapping between lowercase, UPPERCASE, Sentence case, Title Case, and Capitalized Case — so you don’t have to do it by hand.

URL slugs

Human-written titles contain diacritics, punctuation, and capitals not suitable for URLs. The Slug URL transformation removes these in one step: Best case converter! becomes best-case-converter. The result is an ASCII string, lowercase, with hyphens as separators.

Clean data for import

Spreadsheets and CSV exports often come with inconsistent formatting: trailing spaces, mixed casing, duplicates, empty lines. The text transformation group fixes this with one click: Trim, Reduce spaces, Remove empty lines, Sort A→Z, Remove duplicates.

Convert code identifiers between conventions

Paste a list of names, pick the target format, and copy. The tool splits text using common word boundaries (spaces, hyphens, underscores, dots, slashes, and camelCase/PascalCase transitions) and assembles it in the selected style.

Typical use cases

• Convert uppercase text to lowercase accidentally typed with Caps Lock enabled.
• Format article titles in Title Case or Sentence case for editorial style.
• Generate URL slugs from headings in any language.
• Normalize lists of surnames, keywords, or product titles before importing.
• Convert variable and class names between coding conventions.
• Count words, characters, and paragraphs with built-in stats.

Tips

• For English titles, leave Smart Title Case and Protect proper names switched on.
• For Polish, German, or Turkish text, select the language from the Language Rules list before converting.
• Unicode stylizations are decorative. Screen readers and search engines usually don’t interpret them as regular letters, so avoid them in content that must be accessible or indexed.

Privacy & performance

All conversions are done locally in your browser. The tool works on all modern browsers (Chrome 116+, Firefox 115+, Safari 14+, Edge 116+).

FAQ

• How do I convert uppercase to lowercase?

  Paste your text into the input box and click the lowercase button. The entire text will be converted to lowercase in one click, and you can instantly copy the result.

• What’s the difference between Title Case and Capitalized Case?

  Capitalized Case capitalizes the first letter of every word, including short ones. Title Case in Smart mode keeps short conjunctions and prepositions lowercase unless they’re the first or last word.

• Does the converter protect brand names like iPhone or NASA?

  Yes, when the Protect proper names option is enabled. The tool uses a built-in dictionary of about 250 common names — brands, acronyms, countries, cities, days, and months. Names outside the dictionary are handled with default rules.

• Can I convert text with Polish, German, or Turkish letters?

  Yes. First pick the language from the Language Rules list. This is especially important for Turkish (İ/ı) and German (ß/ẞ), where default rules would give incorrect or inconsistent results.

• Is Unicode bold real bold?

  No. Unicode bold uses a special block of mathematical alphabet characters that look bold. They paste anywhere as regular text, so they work on Twitter, Instagram, and other platforms without formatting — but screen readers don’t read them out.

• Is the Case Converter free?

  Yes, within the limits of the free plan. Paid plans remove the daily limit.