Sentence Case Converter
Capitalise the first letter of each sentence, lowercase the rest.
Converter Settings
Sentence case
Characters: 0Words: 0Sentences: 0
What is sentence case?
Sentence case capitalises the first letter of each sentence and lowercases everything else. Boundaries are detected at ., ! and ? followed by whitespace, at the full-width terminators 。 ！ ？ used by Chinese and Japanese, at the Devanagari danda । and the Arabic ؟, and at a hard line break. Decimals like 3.14 and abbreviations like e.g. are not treated as boundaries. All-caps and mixed-case text is normalised to lowercase first, then sentence starts are re-capitalised.
For other capitalisation styles, see Title Case Converter or the Case Converter for UPPER, lower, camelCase, and more.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Converting a shouted or title-cased paragraph back to readable prose.
- Normalising headings that were entered in mixed styles.
- Fixing text pasted from a source that upper-cased everything.
- Applying sentence case across several paragraphs consistently.
- Preparing copy that a house style requires in sentence case.
Frequently Asked Questions
- How does it find a sentence boundary?
- With the shared sentence splitter, not a bare `[.!?]` search. That matters immediately: a decimal like 3.14 and an abbreviation like e.g. are not sentence ends, so "it costs 3.14 dollars" no longer becomes "it costs 3.14 Dollars".
- Are line breaks treated as new sentences?
- Yes. A hard newline starts a new sentence, so pasting a bulleted list capitalises every item rather than only the first — the behaviour that a punctuation-only rule gets wrong on almost every list.
- Does it lowercase the rest?
- Yes, which is what makes it useful on SHOUTED or Title Cased text — but it also lowercases proper nouns and acronyms. "NASA" becomes "Nasa" and "Paris" becomes "paris" mid-sentence; there is no reliable way to tell a name from an ordinary word.
- When should headings use sentence case?
- Increasingly by default — it is the house style at the BBC, Google and most modern documentation, because it reads faster and sidesteps every argument about which small words to capitalise. Title case survives mainly in book titles and US news headlines.
- How is this different from capitalising each word?
- Entirely. Sentence case capitalises the first word of each sentence; title case capitalises the significant words in a heading. Applying title case to a paragraph is a common accident and makes the text markedly harder to read.
- What happens to proper nouns and acronyms?
- They are lowercased along with everything else, because a converter cannot tell `Apple` the company from `apple` the fruit without a dictionary. That is the main reason sentence-casing needs a human pass afterwards.
Common errors and gotchas
- Lower-casing proper nouns and acronyms, which sentence case should preserve.
- Splitting sentences on every period, which breaks abbreviations like 'e.g.'.
- Missing sentences that end with a question or exclamation mark.
- Assuming one space after a period, which fails on double-spaced text.
- Applying it to text where capitalisation carried meaning, such as a code identifier.
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