Sentence Case
Convert text to sentence case — capitalizes the first letter of each sentence and lowercases the rest. Free, instant, client-side case converter.
🔒 100% Client-Side Processing
Your data is processed entirely in your browser and never transmitted to any server.
0 / 100M Limit
Common Use Cases
Fixing pasted headlines
Convert ALL-CAPS or Title Case text from press releases and PDFs into normal sentence capitalization for body copy.
Normalizing user submissions
Clean up form input and imported comments where users typed entirely in caps or lowercase.
Editing subtitles and captions
Reformat caption files that arrived in uppercase into natural sentence-style text.
Frequently Asked Questions
- How does the sentence case converter decide what to capitalize?
- It lowercases everything, then capitalizes the first letter of the text and any letter following a sentence terminator (. ! ?). The result mimics natural prose capitalization.
- Will proper nouns stay capitalized?
- No — the converter cannot recognise names, so "i met john in paris." becomes "I met john in paris." Re-capitalize proper nouns manually after converting.
- What counts as the end of a sentence?
- A period, question mark or exclamation mark followed by whitespace. The very start of the text is treated as a boundary too, so the first word is always capitalised regardless of what precedes it.
- Why did my abbreviation start a new sentence?
- Because the rule is punctuation-based and cannot tell an abbreviation from a full stop. "e.g." and "Dr." and "U.S." will each trigger a capital on the following word. There is no reliable way to distinguish them without a dictionary, so the safer behaviour is to over-capitalise visibly rather than miss real sentence starts silently.
- How is this different from title case?
- Sentence case capitalises only the first word of each sentence, which is the standard for body copy and for most modern UI text. Title case capitalises most words in a string and belongs in headlines — the Title Case Converter applies that instead, including the rules about which short words stay lowercase.
- Is my data private when I use this tool?
- Yes. This tool runs entirely in your browser using client-side JavaScript — nothing you type is transmitted to, logged by, or stored on any server. You can safely process confidential text, tokens, or code.