Sentence Case
Capitalize only the first letter of each sentence.
How to Use Sentence Case
- 1Paste your text in the input area
- 2Sentence case is applied instantly
- 3Copy or download the result
About Sentence Case
Sentence Case Converter formats text the way a properly written sentence should look: the first letter of each sentence is capitalized, and the rest of the words are lowercased. This is useful for fixing text accidentally typed in ALL CAPS, correcting mixed-case content copied from PDFs, or normalizing user-submitted text before display.
The tool detects sentence boundaries by looking for periods (.), exclamation marks (!), and question marks (?) followed by a space or end of text, then capitalizes the first alphabetic character of the next sentence. All other text is lowercased.
Processing runs instantly in your browser with no server involved. Sentence case is the recommended format for body text, descriptions, form labels, and email subjects that should read naturally without aggressive capitalization.
Key Features of Sentence Case
- Capitalizes only the first word of each sentence
- Lowercases all other words for clean, natural-reading text
- Detects sentence boundaries on ., !, and ? punctuation
- Instant real-time conversion as you type
- One-click copy button for the formatted output
- Download result as a plain .txt file
- Preserves line breaks and paragraph structure
- Runs entirely in-browser with no data transmission
Examples
Fix text accidentally typed in ALL CAPS
Convert a block of all-uppercase text into readable sentence case.
Input
THE MEETING IS SCHEDULED FOR FRIDAY. PLEASE CONFIRM YOUR ATTENDANCE. BRING YOUR REPORTS.
Output
The meeting is scheduled for friday. Please confirm your attendance. Bring your reports.
Normalize mixed-case content from a PDF copy-paste
Clean up irregularly cased text pasted from a scanned document.
Input
THIS SECTION COVERS the basics. KEY POINTS are outlined below. MORE DETAILS follow.
Output
This section covers the basics. Key points are outlined below. More details follow.
Common Use Cases
- Converting ALL-CAPS text from old documents into readable lowercase sentences
- Normalizing user-submitted form text before storing or displaying it
- Correcting copy-paste artifacts from PDFs with inconsistent casing
- Formatting email subject lines that should read as normal sentences
- Fixing body text that was accidentally entered in title or uppercase format
- Preparing text for NLP pipelines that expect sentence-cased input
Troubleshooting
Proper nouns like names and brand names are lowercased
Solution
Sentence Case lowercases everything except the first word of each sentence — it cannot distinguish proper nouns from common words. After applying sentence case, manually re-capitalize proper nouns, names, and acronyms.
Abbreviations ending in a period (e.g., "Dr.", "Mr.") trigger a new sentence
Solution
The tool treats any period followed by a space and a letter as a sentence boundary. Abbreviations like "Dr." will cause the next word to be capitalized. Manual correction may be needed after conversion.
The "I" pronoun is not capitalized mid-sentence
Solution
The standalone "I" pronoun requires special-case logic not included in basic sentence case conversion. After applying the tool, do a quick find-replace to correct all occurrences of standalone " i " to " I ".
Frequently Asked Questions
How does the tool detect sentence boundaries?
Sentences are identified by a period (.), exclamation mark (!), or question mark (?) followed by whitespace and the next word. The first alphabetic character after that boundary is capitalized. This covers the vast majority of English sentence endings.
Does it preserve proper nouns?
No — the tool lowercases everything except the first word of each sentence. It has no way to distinguish proper nouns from common words, so names, brands, and places will be lowercased and need manual correction afterward.
What is the difference between sentence case and title case?
Sentence case capitalizes only the first word of each sentence, mirroring how body text is written in prose. Title case capitalizes most words in a heading following editorial rules. Use sentence case for natural-reading text; use title case for publication headings.
Does the "I" pronoun get capitalized?
Basic sentence case does not automatically capitalize the standalone "I" mid-sentence since it is treated as a regular lowercase word. After conversion, use a find-replace to change all occurrences of " i " (with spaces) to " I ".
Will abbreviations like "Dr." or "etc." cause problems?
Yes, abbreviations ending in periods can be misinterpreted as sentence endings. The word following "Dr." will be capitalized because the tool sees the period as a sentence boundary. Manual review is recommended when text contains many abbreviations.
Is there a text length limit?
No. All processing runs locally in your browser with no server overhead. You can paste and convert documents of any length without performance issues.
Is my text stored or transmitted anywhere?
No. Conversion runs entirely in client-side JavaScript. Your text never leaves your browser and is not stored, logged, or sent to any server.
Does it handle multiple paragraphs?
Yes. The tool processes your entire input including multiple paragraphs and line breaks. Each sentence within any paragraph is correctly detected and formatted. Blank lines between paragraphs are preserved.