Live demo (works without JavaScript):
UPPERCASE
SAMPLE INPUT — PASTE ANYTHING AND WATCH THE RESULT UPDATE.Title / Sentence case (first letter of each sentence)
Sample Input — Paste Anything And Watch The Result Update.lowercase
sample input — paste anything and watch the result update.Swap case (invert each letter)
sAMPLE INPUT — PASTE ANYTHING AND WATCH THE RESULT UPDATE.Written by Jane Smith · Reviewed by Sarah Mitchell · July 27, 2026
Convert text between uppercase, lowercase, title case, sentence case, or toggle case.
This case converter rewrites text between five different capitalization styles with a single click. Paste any block of text, a headline, a sentence, or a product name, and choose the mode that fits the job: upper, lower, title, sentence, or alternating case. The conversion runs instantly in your browser, so long documents and repeated edits cost nothing and never leave your device.
The tool takes whatever text sits in the input box and rebuilds it according to the mode you select, replacing the contents of the output area with the result. Uppercase mode forces every letter to its capital form, ideal for headings, acronyms, or shipping labels. Lowercase mode does the reverse, which is handy when imported text arrives in ALL CAPS. Alternating case flips each letter's state, producing the playful style used in meme text and informal messages. The character count of the output is shown below the box so you can confirm nothing was lost in conversion.
Title case capitalizes the first letter of every word and lowercases the rest, following the pattern used in most book titles and article headlines. Sentence case capitalizes only the first letter of the text and the first letter after each sentence-ending punctuation mark, a period, exclamation point, or question mark, while leaving the remainder lowercase. The uppercase and lowercase modes are exact transformations of the alphabet, and alternating case works letter by letter, switching between capitals and lowercase as it moves across the input. On the short sample hello world, title mode produces Hello World while sentence mode produces Hello world, which shows the difference between word-level and sentence-level logic at a glance.
Title case treats any run of non-space characters as a single word, so hyphens, apostrophes, and slashes stay inside the word they belong to: well-known becomes Well-Known, and don't becomes Don't. Sentence case relies on sentence boundaries instead of word boundaries, capitalizing the character that follows a period, exclamation mark, or question mark and at least one space. Because the rule accepts any amount of whitespace, even a double space after a full stop still triggers a capital letter. Text pasted without ending punctuation is treated as one sentence, so only the leading character is capitalized.
Text pulled from email clients, PDF viewers, or messaging apps often arrives with quirks: trailing spaces, blank lines, or words glued together by odd characters. This tool transforms everything in place and discards nothing, so what you paste is exactly what gets converted, structure included. It is worth scanning the output before dropping it into a headline, because the title and sentence modes make decisions from punctuation alone and cannot know your intent.
Reach for title case for headings and display text, sentence case for paragraphs and body copy, uppercase for acronyms and emphasis, lowercase for slugs and tag lists, and alternating case only for playful or informal posts. A common workflow is converting a full document to sentence case before proofreading, which forces stray capitals to stand out, then switching individual headings to title case at the end.
Journalists normalizing headlines, students fixing essays that were typed with caps lock on, developers cleaning up user-generated labels, and social media managers standardizing post formatting all reach for this kind of tool daily. It also solves a common annoyance: text copied from email clients or PDF viewers frequently arrives in inconsistent case, and running it through title or sentence mode restores a clean, consistent look in seconds.
The uppercase and lowercase modes rely on the browser's built-in string conversion, which handles accented characters and most of the Unicode alphabet correctly. Alternating case, by contrast, only flips the 26 letters of the basic Latin alphabet, so accented characters and symbols pass through unchanged. Numbers, punctuation, and whitespace are never altered by any mode, preserving the structure of your text.
The upper and lower modes do, through the browser's Unicode-aware string functions. The alternating mode touches only A to Z and a to z, leaving accented letters in their original state.
Yes. The modes transform characters in place and never merge or split lines, so paragraph and list structure stays exactly as you typed it.
Each hyphenated segment is treated as part of one word, so both segments get a capital initial letter, as in First-Class.
Sentence mode treats the whole input as a single sentence, so only the first letter is capitalized unless a period, exclamation mark, or question mark appears later in the text.
Yes, the output count reflects the full transformed text including spaces, so you can compare input and output lengths directly.
The conversion is instant regardless of length because it runs entirely in the browser using the standard string methods of the JavaScript engine.
No. Digits, symbols, and whitespace pass through untouched, so 'Version 2.0' becomes 'version 2.0' in lowercase mode and the numbers keep their value. If a mode ever treats a punctuation mark as part of a word, the page notes it in the explanation above.