Auto Capitalize Sentences
Auto capitalize sentences in one step: fix the first letter of every sentence and every “I”, without touching anything else.
About
Why Auto Capitalize Sentences?
Text typed in a hurry often skips capital letters. This tool lets you auto capitalize sentences and fix capitalization in a single paste, raising only the letters that should be capitals and leaving your wording alone.
It’s gentler than a full case converter, which rewrites every letter. For messy spacing or hidden characters, run the text through the text cleaner too.
Guide
How to Use the Auto Capitalize
Paste text that has missing capital letters, such as a message typed on a phone or a transcript.
The corrected version appears on the right immediately, with a count of how many fixes were made.
Untick “Capitalize the word I” if your text uses “i” on purpose, such as in code or math.
Copy the corrected text or download it as a .txt file.
Features
Key Features
Capitalize first letter of sentence
Every sentence start is fixed, including after quotes and brackets and at the start of each line.
Capitalize “i” automatically
The pronoun and its contractions become I, I’m, I’ll, I’ve, and I’d, while “i.e.” is left alone.
Smart about abbreviations
Common abbreviations such as e.g., etc., Mr., and Dr. don’t trigger a capital after them.
Leaves the rest as written
Names, acronyms, and capitals you typed stay exactly as they are.
Use cases
Who It’s For
Phone and chat text
Fix lowercase text typed quickly on a phone before pasting it into an email or document.
Transcripts and notes
Clean up dictation and meeting notes where sentence starts came out lowercase.
Students
Correct capital letters in a draft before handing it in.
Will it change words that are already capitalized?
No. It only raises lowercase letters at the start of sentences and the standalone word “i”. To force a whole text into one style, use the Case Converter instead.
How does it know where a sentence starts?
A new sentence starts after a period, question mark, exclamation mark, or ellipsis followed by a space, and at the start of each line. That’s how it knows to capitalize after a period but not inside a number like 3.5.
Is this sentence capitalizer free to use?
Yes. It’s a free auto capitalization online tool with no sign-up, and your text never leaves your browser. It’s also a quick capitalization fixer for text you’d rather not retype.