Case Converter
Free online case converter. Convert to UPPER, lower, Title, Sentence, tOGGLE case. No sign-up, works in your browser.
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Case Converter — Six Ways to Change the Capitalisation of Any Text
The case converter applies six distinct capitalisation styles to whatever you paste. It exists
because toUpperCase() and toLowerCase() only
give you two options, and the styles people actually need — title case, sentence case, alternating, inverse —
are not built into any language or platform. Select a style and the result panel updates as you type.
The Six Modes and Exactly How Each One Behaves
Each mode uses a different rule, and the differences matter more than the labels suggest. Knowing which rule you are getting prevents the classic bug where a title ends up as "The Util Box" instead of "The Util Box".
| Mode | Rule | Result |
|---|---|---|
| UPPER CASE | Uppercases every character. | THE UTIL BOX |
| lower case | Lowercases every character. | the util box |
| Title Case | Uppercases the first letter of every word and lowercases the rest of that word. | The Util Box |
| Sentence case | Uppercases the first word and the first word after any full stop, question mark or exclamation mark. | The util box. It works offline. |
| aLtErNaTiNg | Alternates case by character position, starting lowercase at index 0. | tHe uTiL bOx |
| iNVERSE cASE | Flips the case of each character individually, leaving non-letters untouched. | tHE uTIL bOX |
Title Case Lowercases Everything Else — Here Is Why That Is Correct
Look closely at the Title Case row: it lowercases the remaining letters of each word, so
NASA becomes Nasa and
iPhone becomes Iphone. That is not a limitation
to work around — it is the difference between title case and headline-style
capitalisation.
Title case treats every word identically: capital first letter, lowercase the rest. Headline style, by contrast, capitalises articles, short prepositions and conjunctions only when they lead the title, and it deliberately preserves the internal capitals of proper nouns and brand names — which is why you see "The Util Box: 500+ Tools" rather than "The Util Box: 500+ Tools". Preserving existing internal capitals is what slug and headline generators have to special-case, and it is the single most common source of disappointment with naive title-case tools.
If you need the acronym-preserving version for a blog post heading, convert to Title Case here and then repair the handful of proper nouns by hand — that is faster and more reliable than trying to coax a regex to do it.
Where Sentence Case Actually Matters
Sentence case is not a stylistic preference in several important places, and getting it wrong makes text look broken rather than lazy:
- UI buttons and menu labels — the Material Design and Apple Human Interface Guidelines both specify sentence case, not Title Case, so "Save changes" beats "Save Changes".
- Error messages — sentence case reads as calmer and more direct when something has gone wrong.
- Email subject lines and push notifications — sentence case is easier to read in a crowded list and avoids shouting.
- Screen readers — some assistive tech reads all-caps words as acronyms, letter by letter, so "SAVE" can be announced as "S-A-V-E". Sentence case avoids that entirely.
- URLs and slugs — lowercasing before generating a slug prevents mixed-case paths that some servers treat as distinct resources.
Handy Companions for Text Cleanups
Capitalisation is rarely the only problem with pasted text. These handle the rest of the cleanup:
- Remove Line Breaks — collapse hard-wrapped lines back into flowing paragraphs.
- Text Repeater — duplicate a line a fixed number of times for test data and padding.
- Alphabetize List — sort entries A to Z, useful once casing is consistent.
- Reverse Text — reverse by character or by word.
- Invisible Character — strip zero-width and non-breaking characters that break search matching.
Conversion runs entirely in the browser, so you can safely paste client names, draft posts or unpublished copy without it going anywhere.