Sentence Case Converter

Lowercase text and capitalize sentence starts. Paste or type your text and the result updates instantly. Everything runs in your browser, so nothing is uploaded, nothing is stored, and there is no limit on how much text you can process.

What Sentence Case Converter does

Sentence case capitalises the first word of each sentence and leaves the rest alone. Sentence boundaries are detected from full stops, question marks and exclamation marks, which means abbreviations such as "e.g." can trigger a false boundary. Proper nouns are not restored, because there is no reliable way to tell a name from an ordinary word without a dictionary.

Your text never leaves your device

This tool is written in JavaScript and runs locally in the browser tab. No text is transmitted to a server, none is written to a log, and none is retained after you close the page. That makes it safe for drafts, client work and anything else you would rather not paste into an online form.

Why results can differ from other tools

Text processing involves judgement calls: what counts as a word, whether a hyphenated compound is one token or two, how a line ending is treated. Different tools resolve these differently, so a small discrepancy between this and a word processor is expected rather than an error.

Worked example

Run on a short sample so you can see exactly what changes before pasting your own text: