Sentence case converter
Fix capitals so each sentence starts correctly. Your text never leaves your device.
- Your text is never uploaded
- Processed on your device
- Works offline
- Free, no sign-up
Empty
Result updates as you type
The result appears here as soon as you type or open a file.
Settings
Leaves fully-uppercase words unchanged.
How it works
Paste your text
Type, paste or open a text file. ALL CAPS or messy capitals work fine.
Convert to sentence case
Each sentence starts with a capital and the rest is lowercased, except kept acronyms.
Copy or download
Copy the fixed text or download it as a TXT file.
What sentence case does
Sentence case capitalises the first letter of every sentence and lowercases the remaining letters, while keeping punctuation, numbers, line breaks and spacing exactly as they are. It turns HELLO WORLD. HOW ARE YOU? into Hello world. How are you? This is the standard casing for paragraphs, essays, emails and product descriptions, and the fastest way to repair text accidentally typed with Caps Lock on.
The converter finds sentence boundaries at full stops, question marks and exclamation marks followed by spacing or a line break. The pronoun I is always capitalised as I, and common abbreviations such as e.g., i.e., Mr. and Dr. do not falsely start new sentences. Review personal names and place names afterwards, because automatic casing cannot identify every proper noun.
Keep acronyms or reset everything
With Keep acronyms on, fully-uppercase words longer than one letter such as NASA, USA, HTML and BBC are preserved while everything else is lowercased first. This is ideal for technical writing where acronyms must survive. For example, I WORK AT NASA becomes I work at NASA with the option on, keeping both the pronoun I and the acronym intact.
Turn Keep acronyms off when the entire paragraph was typed with Caps Lock and no word should stay uppercase. The same example then becomes I work at nasa, so you can re-add capitals to the few acronyms by hand. Pasting only the section that needs fixing avoids changing headings or code samples elsewhere in your document.
Private by design: convert without uploading
This sentence case converter runs entirely in your browser. Your paragraphs are processed on your own device with a small Unicode-aware script that respects accented letters and multiple languages. Nothing is uploaded, nothing is saved after you close the page, and it works offline after the first visit. Check the live preview before you copy or download.
That matters for drafts, essays and work documents you are polishing. There is no sign-up, no watermark and no daily limit, and you can process up to 10 files of 500 MB each in one go. Close the tab when you have finished with sensitive text.
Questions
Is my text uploaded to a server?
No. Conversion happens inside your browser. Your text never leaves your device.
How do I fix text typed with Caps Lock?
Paste it here and convert. Turn off Keep acronyms if every word is uppercase and should be reset.
Will it change proper nouns?
Words inside a sentence become lowercase except kept acronyms. Check names like London or Maria afterwards.
Is it free?
Yes. Free to use, with no sign-up, no watermark and no daily limits.
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