Updated for 2026. Our case converter is a free online tool that changes the letter case of any text instantly. Paste your text into the box above, pick a case, and the case conversion happens in your browser — nothing is uploaded, nothing is stored, and there is no limit on how much text you convert.

Whether you need to convert upper case to lower case after leaving Caps Lock on, turn a heading into proper Title Case, or reformat a variable name into camelCase, this text case converter handles all twelve formats from a single box. It works on desktop, tablet and mobile, and it never changes your original words — only the capitalization.

1. What Is a Case Converter and How Does It Work?

A case converter — also called a case changer, a letter case converter or a text case changer — is a tool that rewrites the capitalization of text without touching the words themselves. You give it a sentence, you choose a target case, and it gives the same sentence back with different capital letters.

This matters more often than people expect. A block of text typed with Caps Lock on has to be fixed before it can be sent. A headline pasted from a website arrives in the wrong style. A list of names copied from a spreadsheet comes back in ALL CAPS. In every one of those situations, retyping is slow and error-prone. An online case converter does the whole job in a single click.

Why Convert Case Online Instead of Retyping?

• Speed. Converting ten thousand words takes the same fraction of a second as converting ten.
• Accuracy. Retyping introduces typos. A case converter tool only changes capitalization, never spelling.
• Consistency. Every heading follows the same rule, every time.
• Privacy. The conversion runs in your browser. Your text never leaves your device.

The Twelve Case Formats Supported

2. Every Case Converter in One Page

Most people arrive here looking for one specific conversion. Rather than sending you to a different page for each one, every case converter below is the same box at the top of this page — you simply click a different button.

Uppercase to Lowercase Converter

The most requested conversion of all. An uppercase to lowercase converter takes text shouted in capitals and brings it back to normal. Paste the text, click Lowercase, and THE MEETING IS AT NOON becomes the meeting is at noon. If you want the first letter of each sentence kept, use Sentence Case instead — that is the smarter upper case to lower case converter for real paragraphs.

Lowercase to Uppercase Converter

The reverse. A lowercase to uppercase converter turns quiet text into a banner. Click Uppercase and every letter becomes a capital, accents included. This is the lower case to upper case converter you want for labels, warnings, spreadsheet headers and short titles that need to stand out.

Capital Letter Converter

When people search for a capital letter converter they usually mean one of two things: make everything capital, or capitalize the first letter of each word. The first is the Uppercase button; the second is Proper Case. If you need to convert to capital letters for a whole column of names, Proper Case is almost always the one you want.

All Caps Converter

An all caps converter does exactly what the name says. It is the same button as Uppercase, and it is the fastest way to produce ALL CAPS text for a button label or a heading. To go the other way, the all caps to lowercase conversion is the Lowercase button — or Sentence Case if you want readable sentences back rather than a wall of small letters.

Sentence Case Converter

The sentence case converter is the one most people should use and most people overlook. It capitalizes the first letter of every sentence and leaves everything else alone — except acronyms and brand names, which it protects. It is the right tool for fixing a paragraph, an email or a product description that arrived in the wrong case.

Title Case Converter

A title case converter formats a headline properly: major words capitalized, small words left alone. Ours applies Chicago Manual of Style rules, so the lord of the rings becomes The Lord of the Rings and not The Lord Of The Rings. Section 5 breaks down exactly which words get a capital and why.

Proper Case Converter

The proper case converter capitalizes the first letter of every word with no exceptions. It is the right choice for names, cities and product labels — anywhere you want New York City rather than New York city. It also handles McDonald, O'Brien and Jean-Luc correctly, which most tools do not.

camelCase, snake_case and kebab-case Converter

For developers, the same box doubles as a camel case converter, a snake case converter and a kebab case converter. Paste any string in any format — spaces, underscores, hyphens or existing camelCase — and the tool works out the word boundaries before rebuilding it in the style you pick.

3. How to Convert Upper Case to Lower Case

This is the single most common reason people look for a case converter. You typed a whole paragraph with Caps Lock on, or someone sent you a document in ALL CAPS, and now you need to convert upper case to lower case without starting over.

1. Copy your text. Select it in Word, Excel, an email or a web page and press Ctrl + C (Cmd + C on Mac).
2. Paste it into the box above. Click inside the yellow text area and press Ctrl + V, or use the Paste button.
3. Click Lowercase. Every capital letter becomes lower case immediately.
4. Copy the result. Press the Copy button, or use Download to save it as a .txt file.

Lower Case Is Not Always the Right Answer

If your text contains real acronyms — NASA, HTML, CEO, USB — a plain lower case converter destroys them. That is why you should reach for Sentence case instead when you are fixing a paragraph. Our sentence case option protects acronyms, brand names such as iPhone and eBay, and abbreviations such as p.m. and U.S.A., so THE CEO OF NASA ARRIVED AT 3 P.M. becomes The CEO of NASA arrived at 3 p.m. and not the ceo of nasa arrived at 3 p.m.

4. How to Convert Lower Case to Upper Case

The reverse job is just as common. To convert lower case to upper case — for a banner, a warning label, a spreadsheet column or a set of headings — paste the text above and click Uppercase. Every letter becomes a capital letter, accented characters included: café becomes CAFÉ, and the German straße correctly becomes STRASSE.

If you only want the first letter of each word capitalized, use Proper Case instead. If you want a properly formatted headline, use Title Case — the two are not the same thing, and section 5 explains exactly why.

5. Title Case Rules: AP, Chicago, MLA and APA Compared

Title case is the style used for book titles, article headlines and section headings. The idea is simple — capitalize the important words, leave the small ones alone — but the exact rules differ from one style guide to the next, which is why a good title case converter has to pick a standard and apply it consistently.

Our Title Case button follows the Chicago Manual of Style, 18th edition, the most widely used standard for books and long-form writing. Here is how the four major guides compare on the points that actually cause disagreement.

Title Case in Practice

Applying the Chicago rules to a few real titles shows what the tool actually does:

• the lord of the rings → The Lord of the Rings — “of” and the second “the” stay lower case.
• what are you waiting for → What Are You Waiting For — “for” is normally lower case, but it is the last word, so it is capitalized.
• a walk through the park → A Walk Through the Park — “through” has five letters, so it takes a capital.
• a walk with the dog → A Walk with the Dog — “with” has four letters, so it stays lower case in Chicago style.
• the guide: a new beginning → The Guide: A New Beginning — the first word after a colon is always capitalized.

6. Sentence Case vs Title Case: What Is the Difference?

These two are constantly confused, and picking the wrong one is one of the most visible signs of sloppy formatting. The difference is easy once you see it side by side.

If you are unsure which to use, sentence case is the safer default. Research on readability consistently finds that sentence case is faster to scan, and almost every major design system — Google Material, Apple’s guidelines, Microsoft’s — now recommends it for interface text. Reserve title case for genuine titles.

7. Proper Case, Capital Case and All Caps Explained

Three more terms come up constantly, and they are not interchangeable.

Use the all caps converter sparingly. Long stretches of capital letters are measurably harder to read, because the eye relies on the shape of lower case words to recognize them quickly. In email and chat, all caps also reads as shouting. It works for short labels, buttons and warnings — not for paragraphs.

Proper Case Handles Names Correctly

A naive capital letter converter turns ronald mcdonald into Ronald Mcdonald and o'brien into O'brien. Ours returns Ronald McDonald and O'Brien, and keeps hyphenated names intact: jean-luc picard becomes Jean-Luc Picard.

8. How to Change Case in Microsoft Word

You do not always need a web tool. Word has a built-in Change Case command, and it is worth knowing.

1. Select the text you want to change.
2. Go to the Home tab and find the Aa button in the Font group.
3. Choose Sentence case, lowercase, UPPERCASE, Capitalize Each Word or tOGGLE cASE.
4. Or skip the menu entirely and press Shift + F3 to cycle between the three main options.

9. How to Change Case in Excel and Google Sheets

Excel has no Change Case button. Instead it gives you three formulas, and once you know them you can convert case in Excel across thousands of rows in seconds. Google Sheets uses exactly the same three.

Turning Formulas Into Real Text

A formula result is still a formula. To keep the converted text after deleting the original column, select the formula cells, press Ctrl + C, then right-click and choose Paste Special → Values. Only then can you safely delete column A.

If you would rather skip formulas altogether, paste the column into the case converter at the top of this page — it keeps one row per line — then copy the result straight back into your spreadsheet.

10. Changing Case in Google Docs, Notepad++ and Code Editors

11. Programming Case Styles: camelCase, PascalCase, snake_case and kebab-case

Developers deal with a different family of case formats. Every language has its own convention, and mixing them up makes code look careless. Our converter handles all five, and it understands whatever you feed it — it will read helloWorldFoo, hello_world_foo and Hello World Foo as the same three words.

What Is Camel Case, Exactly?

Camel case — sometimes written camelCase, camel casing or camelback case — joins words together with no spaces and capitalizes the first letter of every word except the first. The humps of capital letters in the middle are where the name comes from. Upper camel case is simply another name for PascalCase, where even the first word takes a capital.

12. Converting Case in Code: Python, JavaScript, Java, PHP and SQL

If you are writing a script rather than fixing a document, every language has built-in methods for case conversion.

Python

text = "the quick brown fox"

text.upper()        # THE QUICK BROWN FOX
text.lower()        # the quick brown fox
text.title()        # The Quick Brown Fox
text.capitalize()   # The quick brown fox
text.swapcase()     # tHE QUICK BROWN FOX

JavaScript

const text = "the quick brown fox";

text.toUpperCase();   // THE QUICK BROWN FOX
text.toLowerCase();   // the quick brown fox

// Sentence case
text.charAt(0).toUpperCase() + text.slice(1);

// Proper case
text.replace(/\b\w/g, c => c.toUpperCase());

Java

String text = "the quick brown fox";

text.toUpperCase();   // THE QUICK BROWN FOX
text.toLowerCase();   // the quick brown fox

PHP and SQL

// PHP
strtoupper($text);   // THE QUICK BROWN FOX
strtolower($text);   // the quick brown fox
ucwords($text);      // The Quick Brown Fox
ucfirst($text);      // The quick brown fox

-- SQL
SELECT UPPER(name), LOWER(name) FROM users;

13. Common Problems and How to Fix Them

14. Frequently Asked Questions

15. Start Converting

Whatever you call it — a case converter, a case convertor, a case changer, a letter case converter, a text case converter or simply a tool to convert case online — the job is the same: take your text, fix the capitalization, give it straight back. No sign-up, no upload, no waiting.

Scroll back to the box at the top, paste your text, and pick the case you need. The tool is maintained and kept current for 2026. If you use it often, bookmark this page — the online case converter loads instantly and works offline once the page is open.