Sentence Case Converter

What sentence case changes in your text

Seven changes happen when text is converted to sentence case:

1. The first letter of each sentence is capitalized.
2. Every other letter is lowercased.
3. A new sentence starts after a period, question mark or exclamation point.
4. The pronoun "I" is capitalized wherever it appears.
5. Acronyms such as NASA, API and UI keep their capitals, even in text typed in all caps.
6. Brand names with a capital inside the word, such as iPhone, macOS and eBay, are kept as typed.
7. Punctuation, spacing and line breaks stay exactly where they were.

What the list does not include is names – and that is the part to check.

What the converter leaves for you to check

The converter cannot tell which words are proper nouns, so it lowercases every one of them except a sentence's first word and known acronyms. Whether “Paris” is a city or “March” is a month depends on meaning, and the converter works from the shape of each word.

Which capitals does sentence case need to keep?

Three groups of capitals belong in sentence case that the converter does not keep.

Names of people and places lose their capitals

Meeting With John Smith In Paris On Monday → becomes Meeting with john smith in paris on monday

After converting, scan for names of people, companies, cities and countries, and restore their capitals.

Days, months and proper adjectives follow names

Days of the week, months, holidays, languages and nationalities such as English and French, and adjectives formed from names such as Victorian are all proper nouns. Sentence case keeps them capitalized; the converter does not.

APA keeps a capital after a colon in titles

In APA sentence case, the first word of a subtitle after a colon is capitalized, along with proper nouns (APA Style). The converter lowercases it, so fix that word by hand:

Title Case Rules: A Practical Guide → Title case rules: a practical guide → corrected to Title case rules: A practical guide

How the rule changes in ordinary sentences is covered in Do You Capitalize After a Colon?

Where sentence case is the required style

Sentence case is required in three places: the APA reference list, AP news headlines and product interfaces.

Which style guides require sentence case?

Two of the four major guides call for sentence case in specific places. The full comparison of their title rules is in Title Capitalization Rules by Style Guide

APA reference titles use sentence case

Titles of articles and books in an APA reference list use sentence case, while journal names keep title case. The first word after a colon is capitalized, as shown above. More in Citing Titles in APA: Book vs Article Formatting

Self-Report Measures in Clinical Research → becomes Self-report measures in clinical research

AP news headlines capitalize only the first word and proper nouns

AP writes news headlines in sentence case: only the first word and proper nouns are capitalized, and the first word after a colon is always uppercase (AP Stylebook). Titles of books and films still take title case, as explained in AP Style Headlines: Capitalization Rules

Why did product interfaces move to sentence case?

Material Design 3 asks for sentence case across all interface text – titles, headings, buttons, menu items and navigation – and keeps capitals only for product and brand names (Material Design 3). Many product teams follow the same convention for buttons and labels.

Sentence case and title case side by side

Title case suits the titles of works and headings your style guide sets that way; sentence case suits body text, interfaces and APA references. The longer comparison is in Title Case vs Sentence Case: Which to Use and When, and headlines go through the title case converter.

Sentence case in Word, Google Docs and Excel

Of the three common editors, only Word has sentence case built in.

Word has a built-in Sentence case option

Select the text, open Home, click Change Case (the Aa button) and choose “Sentence case”. Word does not recognize proper nouns either, so check names afterwards.

Google Docs has no sentence case command

Format → Text → Capitalization offers only lowercase, UPPERCASE and Title Case (How-To Geek). Paste the text into the converter above and copy the result back.

Excel needs a formula for sentence case

Excel has no sentence case function, so combine four text functions:

=UPPER(LEFT(A1,1))&LOWER(MID(A1,2,LEN(A1)))

It capitalizes the first letter and lowercases everything after it. That means it handles one sentence per cell and turns acronyms like NASA into Nasa (Ablebits).