Sentence Case Converter

Capitalize the first letter of every sentence — free, instant, runs in your browser.

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What is Sentence case?

Sentence case capitalizes the first letter of the text and the first letter after every sentence-ending mark (. ! ?) followed by whitespace; everything else is lowercased — exactly like ordinary prose.

Sentence case examples

hello world. this is an example. → Hello world. This is an example.
WELCOME TO OUR SITE! we are glad you came. → Welcome to our site! We are glad you came.
first point here. second one follows? yes, a third. → First point here. Second one follows? Yes, a third.

Where is Sentence case used?

Sentence case is the default for body copy, product UI strings, help text and documentation. Major design systems — including Google's Material Design and Apple's Human Interface Guidelines — prefer sentence case over Title Case for headings and buttons because it reads more naturally and is easier to apply consistently.

A note on proper nouns

Because the converter lowercases everything first, proper nouns lose their capitals: 'paris is lovely' becomes 'Paris is lovely', but 'I love Paris' becomes 'I love paris'. Give names and places a quick manual check after converting.

Common mistakes when converting case

Expecting editorial Title Case. The Title Case button capitalizes every word, including short ones: "the lord of the rings" becomes "The Lord Of The Rings". Style guides like AP and Chicago keep words such as "of", "the" and "and" lowercase, so adjust those by hand afterward.
Losing apostrophes. Word-based styles (Title Case, camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE) split on anything that is not a letter or digit, so "don't stop" turns into "Don T Stop" or "don_t_stop". Remove or restore apostrophes after converting.
Sentence case and proper nouns. Sentence case lowercases the whole text, then capitalizes only the first letter of each sentence, so "i visited NASA in june. it was fun." becomes "I visited nasa in june. It was fun." Re-capitalize names and acronyms yourself.

Pro tips

Rescue a Caps Lock accident with InVeRsE CaSe. Text typed as "hELLO wORLD" while Caps Lock inverted your Shift key flips back to "Hello World" in one click.
Acronyms split cleanly. "HTMLParser" converts to "htmlParser" with camelCase and "html_parser" with snake_case, because the word splitter detects where an acronym ends and the next word begins.
Only letters alternate. In aLtErNaTiNg CaSe, digits, spaces and punctuation stay in place and do not break the pattern: "abc 123 def" becomes "aBc 123 dEf".

Frequently asked questions

What is the difference between Sentence case and Title Case?

Sentence case capitalizes only the first word of each sentence ('The quick brown fox'), while Title Case capitalizes every word ('The Quick Brown Fox'). Sentence case is used for prose and UI copy; Title Case for headlines.

How does the tool detect the start of a sentence?

It capitalizes the first letter of the whole text and any letter that follows a period, exclamation mark or question mark plus whitespace. Abbreviations like 'e.g.' can fool this simple rule, so review tricky sentences.

What happens to proper nouns in Sentence case?

They are lowercased like every other word — 'I visited London' becomes 'I visited london'. Capitalize names, places and brands again by hand after converting.

Other case converters

Or switch between every style in one place on the Case Converter homepage.