Capitalize Each Sentence

Capitalize Each Sentence raises the first letter of every sentence to uppercase while leaving all the other letters exactly as you typed them. It is the gentle way to fix capitalisation, adding the missing leading capitals without touching the casing of any word in the middle of your sentences.

It is perfect for text that is mostly correct but starts sentences in lowercase, such as quick notes, chat messages, or transcribed speech. Because it never lowercases anything, it protects proper nouns, brand names, acronyms, and any intentional capitalisation you already have, so nothing you carefully typed gets undone.

The tool detects sentence starts after full stops, question marks, exclamation marks, and line breaks, then capitalises the first letter that follows. Everything runs locally in your browser using JavaScript, so your text is never uploaded, and the corrected version appears instantly with a count of how many sentence starts were capitalised.

Features

• Capitalises the first letter of each sentence and leaves every other letter unchanged.
• Preserves proper nouns, brand names, and acronyms because it never lowercases text.
• Detects sentence starts after full stops, question marks, exclamation marks, and line breaks.
• Keeps existing correct capitalisation intact so your work is never undone.
• Updates the output live as you type or paste new text.
• Handles multi-paragraph passages, capitalising the start of each one.
• Runs instantly and privately with no account, no upload, and no size limit.

How to use Capitalize Each Sentence

1. Paste or type the text whose sentence starts you want to capitalise.
2. The corrected text appears instantly with each sentence beginning in uppercase.
3. Check the statistics panel to see how many sentence starts were capitalised.
4. Edit the text further if needed and watch the output update live.
5. Copy the result to your clipboard or export it as a TXT file.

Benefits

• Fixes lowercase sentence starts without disturbing any other capitalisation.
• Protects proper nouns and acronyms that a full sentence-case tool might flatten.
• Cleans up quick notes, chat logs, and transcripts with minimal risk of side effects.
• Works across multiple paragraphs so long passages are corrected consistently.
• Keeps private text secure because everything runs locally in your browser.
• Gives instant feedback on how many sentence starts were changed.

The key difference between this tool and a full sentence-case converter is that it is non-destructive: it only ever adds a capital at the start of a sentence and never changes the case of the words that follow. That makes it the safer choice when your text already contains correctly cased names, technical terms, or stylised words that you do not want altered.

Sentence boundaries are found using terminal punctuation and line breaks, so text without clear punctuation, or sentences separated only by spaces, may not all be detected. If your content needs its whole casing normalised rather than just the leading letters fixed, the Sentence Case Converter is the better fit, and it offers an option to preserve acronyms during that heavier transformation.