Case Converter

What this tool does

A case converter changes letter case and leaves the rest of the string alone. This case converter supports UPPERCASE, lowercase, Title Case, and Sentence case. Spaces, tabs, line breaks, digits, and punctuation stay in the same positions. The result is written to a second box so the original paste remains visible. Nothing is uploaded.

That is a different job from a slug or a cleanup. Title Case is not a URL. Sentence case is not “fix my grammar.” The Slug Generator lowercases and then removes punctuation on purpose. The Whitespace Cleaner changes spaces and line breaks, not case. Open those pages when the output should no longer look like the sentence you typed.

How to use

1. Paste the text.
2. Choose UPPERCASE, lowercase, Title Case, or Sentence case.
3. Convert. Copy writes the result. Example uses a two-line sample. Clear empties both boxes.

Empty input is an error. Input over 200,000 characters is refused. Conversion uses the browser locale so i and I follow ordinary English expectations on this site’s English UI.

Example

Example input hello world. this is a TEST. plus a second line second line! becomes HELLO WORLD. THIS IS A TEST. in UPPERCASE. Title Case becomes Hello World. This Is A Test. and Second Line!. Sentence case becomes Hello world. This is a test. and Second line!. The period and the line break do not move.

hello world. this is a TEST.
→ Title Case: Hello World. This Is A Test.

Limits

• Title Case capitalizes the first letter of each whitespace-separated token and lowercases the rest of that token. Small words such as “of” and “and” are not kept lowercase. This is not Chicago or AP title style.
• Sentence case lowercases the whole string, then capitalizes the first letter after the start or after ., ?, or ! plus space. Abbreviations can look like a new sentence.
• Punctuation attached to a word stays attached. “(hello)” in Title Case becomes “(Hello)” because the first letter inside the token is capitalized.
• The tool does not translate, does not remove emoji, and does not rewrite curly quotes.

Names and brand spellings are your problem after the conversion. “iPhone” becomes “IPHONE” or “Iphone” depending on the mode. If you needed a URL, do not Title-Case a heading and then hand-edit hyphens. Use the Slug Generator. If the paste is full of double spaces, clean it first or you will Title-Case the spaces into more spaces.

Paste is never executed as HTML. A <script> in the box is letters, then the same letters in another case.

Work stays in the browser. Convert, copy, and leave. Do not treat the result box as a document store. If you need the same string both as a heading and as a slug, convert case here, then paste the original title into the Slug Generator. Title-casing first and then hyphenating the heading is how people ship Hello-World when they wanted hello-world.

Locale matters at the edges. Turkish dotted and dotless I is the usual surprise in other products. This page uses the browser locale with an English UI and does not offer a locale picker. If you are converting a language that needs a specific casing map, do that conversion where the locale is explicit.