Sentence Capitalizer – Free Online Utility

Automatically Fix Sentence Capitalization

Typing quickly on mobile or taking rough notes often leads to missing capital letters at the start of sentences. Manually fixing these errors can be tedious, especially for long documents. Our Sentence Capitalizer is a smart tool that scans your text and automatically applies standard English capitalization rules.

Smart "I" Correction

A common mistake in informal writing is using a lowercase "i" when referring to oneself. This tool includes a specific rule to find every standalone "i" and convert it to a capital "I", ensuring your writing looks polished and professional.

Preserve Your Formatting

We know that your text structure is important. This tool is designed to be non-destructive; it only modifies the specific characters that need capitalization. All your line breaks, paragraphs, and indentation are preserved exactly as they are. Like all metatool.in tools, it runs 100% in your browser for absolute privacy.

Frequently Asked Questions

It uses a regex to identify the start of sentences (usually preceded by a period, exclamation mark, or question mark) and converts the first letter of each sentence to uppercase.

Yes, this tool also specifically targets lowercase "i" when used as a standalone word (like "i am") and converts it to uppercase "I".

No, the tool preserves all line breaks and multiple spaces. It only targets the specific characters needed for capitalization.

Related Free Tools

Case Converter — Change text case to UPPERCASE, lowercase, camelCase, etc.
Text Cleaner — Strip emojis, non-ASCII, and sanitize your text.