Sentence Case Converter — Free Online Tool
What is Sentence Case Converter?
Sentence Case is the standard capitalisation style used in everyday prose. It capitalises only the first letter of the first word in each sentence, leaving everything else in lowercase (except proper nouns, which you may need to adjust manually).
This converter detects sentence boundaries using full stops, question marks, and exclamation marks, then applies the correct capitalisation. Writers, students, and content creators use it to quickly clean up text that has been pasted in all caps or inconsistent casing.
When to use Sentence Case Converter?
Use Sentence Case for body paragraphs, email copy, social media captions, product descriptions, and any regular prose writing. Content writers converting all-caps headlines into normal text rely on it frequently. Students reformatting copied text from PDFs or presentations use it to fix capitalisation issues.
Marketers preparing A/B test variants for email subject lines often need consistent sentence casing. If your headings require capitalised major words, use the Title Case Converter instead. For programming variable names that start with a lowercase letter, try the Camel Case Converter.
How to use this tool
- 1Paste your text in the input box
- 2Click 'Convert' to apply Sentence Case
- 3Copy the correctly capitalized result
After conversion, review your text for proper nouns (names, places, brands) that should remain capitalised. The tool cannot distinguish proper nouns from common words, so names like 'london' or 'google' will appear in lowercase.
Examples
| Input | Output |
|---|---|
| THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG. | The quick brown fox jumps over the lazy dog. |
| hello world. this is a test. | Hello world. This is a test. |
| MULTIPLE SENTENCES. EACH ONE STARTS WITH A CAPITAL. | Multiple sentences. Each one starts with a capital. |
| camelCase to sentence case example | Camelcase to sentence case example |
| WHY ARE YOU SHOUTING? I AM NOT SHOUTING! | Why are you shouting? I am not shouting! |
Rules & Behavior
- The first word of each sentence is capitalised. The tool detects sentences using period (.), exclamation mark (!), and question mark (?) followed by whitespace.
- All other words are converted to lowercase. This means any existing capitalisation in the middle of a sentence is removed to produce clean, consistent sentence-style text.
- Sentence boundaries are detected by terminal punctuation characters: periods, exclamation marks, and question marks. Abbreviations like Mr., Dr., and U.S. may occasionally cause a false sentence break.
Related Tools
Frequently Asked Questions
What is Sentence Case?
Sentence Case is the standard capitalisation used in everyday writing — only the first letter of a sentence is capitalised, along with proper nouns. It mirrors how you would naturally write a paragraph in an essay, email, or blog post. Most web content and UX copy follows sentence case for readability, making it the most common capitalisation style.
How does sentence detection work?
The converter identifies sentence boundaries using terminal punctuation: period (.), exclamation mark (!), and question mark (?). When one of these characters is followed by whitespace, the next word is treated as the start of a new sentence and capitalised accordingly. Abbreviations like Dr. or U.S. may occasionally trigger a false boundary.
Will it affect proper nouns?
Yes — the tool converts all non-sentence-start words to lowercase, including proper nouns like names, cities, and brands. After conversion, you should manually re-capitalise any proper nouns. For a tool that preserves your existing casing and only adjusts the first letter, consider using a text editor's built-in sentence case feature.
When should I use Sentence Case vs Title Case?
Use Sentence Case for body text, captions, social media posts, and descriptions. Use Title Case for formal titles, blog headings, book names, and subheadings in structured documents. Many modern style guides (including Google's Material Design) prefer Sentence Case for UI labels and buttons.
Does it work with multiple paragraphs?
Yes, the converter handles multiple paragraphs and sentences correctly. Each sentence across every paragraph is processed independently, so the first word after every full stop, question mark, or exclamation mark gets capitalised. You can paste entire articles or documents without any length restriction.