Case Converter: Uppercase, Lowercase, Title Case and 10 More

This case converter rewrites your text in 13 formats at once, from plain uppercase to lowercase to a URL slug. It also gets title case right, so the little words stay small and acronyms like SEO don’t turn into “Seo”.

How to use the case converter

1. Paste or type your text

   Done

   A headline, a client list or a whole paragraph. The character, word and line count updates as you type.

2. Find the format you need

   Done

   All 13 cards update on their own. The top group handles upper and lower case; the bottom group gets text ready for URLs and code.

3. Copy or apply

   Done

   “Copy” takes that result. “Apply” moves it into the main box so you can keep converting, and “Undo” brings back the previous version.

It works as an upper case converter and a lower case converter in one screen, and it respects brands with a capital in the middle, like iPhone or YouTube.

Title case converter rules: AP vs. Chicago

Both styles capitalize the first and last word and every “big” word, and both keep articles and the short conjunctions in lowercase. They split on prepositions. AP lowercases prepositions of three letters or fewer, so “with” and “from” get a capital. Since its 18th edition in 2024, The Chicago Manual of Style only capitalizes prepositions longer than four letters.

Original	AP style	Chicago style (18th ed.)
a room with a view	A Room With a View	A Room with a View
the lord of the rings	The Lord of the Rings	The Lord of the Rings
how to write a slogan that sells	How to Write a Slogan That Sells	How to Write a Slogan That Sells

The “Title Case” card follows the AP cut-off of three letters. If your publication follows Chicago, lowercase “with”, “from”, “into” and “over” by hand. Then check how the headline looks on Google with the SERP simulator.

Sentence case vs title case: which one to use for headlines

Pick one style per surface and stick to it. Sentence case capitalizes the first word and proper nouns. Title case capitalizes the main words. The real difference is tone: sentence case sounds like a person talking, title case sounds like a magazine.

Where	Default pick	Why
Blog headlines and H2s	Sentence case	Microsoft’s style guide uses it even for blog post titles
Buttons, menus and labels	Sentence case	Same guide; it reads like an instruction
Books, movies and reports	Title case	It is the convention for titles of works
Email subject lines	Test both	No study we found settles it
Ad headlines	Either, never all caps	Google Ads bans capitalization that is misused

For emails, send each version to half of your list and let the open rate decide. Before you commit, paste one headline in the box above and compare the “Sentence case” and “Title Case” cards side by side.

Camel case, snake case and URL slugs: which one to use

Format	Example	Use it for
url-slug	write-slogan-sells	Page URLs: no accents, symbols or filler words
kebab-case	how-to-write-a-slogan	CSS classes and file names
snake_case	how_to_write_a_slogan	Python variables and database columns
camelCase	howToWriteASlogan	JavaScript variables and JSON fields
PascalCase	HowToWriteASlogan	Classes and React components

Camel case and snake case also split words that were already joined, so “myVariableName” becomes “my_variable_name” in one click. Need to count the result for a bio or an ad headline? Paste it into the character counter.

Alternating caps generator: how to write SpongeBob mocking text

Alternating caps flips every letter between lower and upper case, so “this is a bad idea” becomes “tHiS iS a BaD iDeA”. The “aLtErNaTiNg” card does it as you type. It starts on a lowercase letter and skips spaces and punctuation when it counts, so the rhythm never breaks.

The style went mainstream in May 2017 with the Mocking SpongeBob meme, according to Wikipedia’s entry on alternating caps. It is plain text, so it pastes into Instagram, TikTok, X or an email as is. For fancier Unicode styles, use the font generator.

Two rules for brands. Keep it short: six words are a joke, sixty are unreadable, and the same Wikipedia entry cites a 1974 study by Coltheart and Freeman that found alternating case impaired word identification. And aim the mockery at yourself or at a villain everyone shares, never at a customer.

Uppercase to lowercase in Word, Excel and Google Docs

Word cycles through lowercase, UPPERCASE and Capitalize Each Word when you select text and press Shift + F3 (Fn + Shift + F3 on a Mac); sentence case lives in the Aa button on the Home tab. Excel has no button, only formulas: =LOWER(A1), =UPPER(A1) and =PROPER(A1). Google Docs keeps it under Format, then Text, then Capitalization. For a long list you also need sorted, convert it here and send it to the list alphabetizer.

Frequently asked questions about the case converter

01

How do I turn all caps to lowercase?

Paste the text into the box above and copy the “lowercase” card, or “Sentence case” if you want capitals back at the start of each sentence. If you typed a whole paragraph with Caps Lock on by accident, use “iNVERSE cASE” instead: it flips every letter back, so the capitals you meant to type stay capitals. In Word, select the text and press Shift + F3 until it reads in lowercase.

02

What words are not capitalized in a title?

In title case, you keep lowercase the articles (a, an, the), the coordinating conjunctions (and, but, for, nor, or) and short prepositions such as at, by, in, of, on and to. Everything else gets a capital, including short verbs like “is” and pronouns like “it”. The list has exceptions: the first and the last word of a title always get a capital, and most guides also capitalize the first word after a colon.

03

What is title case vs upper case?

Upper case puts every letter in capitals: HOW TO WRITE A SLOGAN. Title case capitalizes only the first letter of the important words: How to Write a Slogan. All caps reads like shouting and is harder to scan, which is why style guides keep it for acronyms and short labels. Title case is the usual style for book, movie and song titles, and for many blog headlines.

04

What is sentence case?

Sentence case capitalizes a title or line the way you’d write a normal sentence: only the first word and proper nouns get a capital. “How to write a slogan that sells” is sentence case. Many brands use it for headlines, buttons and app menus because it feels more conversational than title case. The “Sentence case” card above does it for you, keeping acronyms such as SEO intact.