ConvertSuite

Case Converter

Free online text case conversion tool, supporting English letter uppercase to lowercase, lowercase to uppercase fast conversion

Input Text

Conversion Result

💡 Real-time conversion • Mode switching • Ctrl+Enter quick convert • One-click copy result
Real-time conversionBidirectional conversionOne-click copyKeyboard shortcutsFormat preservation

Professional Online Case Converter Tool

Our case converter is a powerful online text processing tool that supports multiple conversion modes including uppercase to lowercase, lowercase to uppercase, and capitalize first letter. Whether you are a programmer converting code variables or a content creator processing document formats, you can quickly complete text case conversion tasks with our tool. The tool is completely free, requires no download or installation, and protects your data privacy.

Uppercase to LowercaseLowercase to UppercaseCapitalizeSentence Case

Features & Applications

Discover 8 conversion modes with their functions and practical use cases

Uppercase to LowercaseSelected

Convert all uppercase letters (A-Z) to lowercase (a-z)

Example:
Input: HELLO World 123!
Output: hello world 123!
Use Cases:Code variables, URL normalization, database fields, email addresses

Lowercase to Uppercase

Convert all lowercase letters (a-z) to uppercase (A-Z)

Example:
Input: hello World 123!
Output: HELLO WORLD 123!
Use Cases:Constants definition, SQL keywords, config keys, title emphasis

Capitalize

First letter of each word uppercase, remaining letters lowercase

Example:
Input: hello WORLD
Output: Hello World
Use Cases:Title case conversion

Uncapitalize

Convert first letter of each word to lowercase

Example:
Input: Hello World
Output: hello world
Use Cases:Reverse title case

Sentence Case

Capitalize first letters of sentences and after punctuation

Example:
Input: hello. good morning!
Output: Hello. Good morning!
Use Cases:Standard sentence format

Inverse Sentence

Lowercase first letters of sentences and after punctuation

Example:
Input: Hello. Good Morning!
Output: hello. good Morning!
Use Cases:Reverse sentence format

Alternating Case

Alternate between uppercase and lowercase by position

Example:
Input: Hello World
Output: hElLo WoRlD
Use Cases:Creative text effects

Inverse Case

Uppercase becomes lowercase and vice versa

Example:
Input: Hello WORLD
Output: hELLO world
Use Cases:Complete case reversal

Tool Features

Our case converter has the following powerful features

Real-time Conversion

Convert as you type, no waiting required, providing the fastest conversion experience

Bidirectional Conversion

Support both uppercase to lowercase and lowercase to uppercase conversion modes

One-click Copy

Quickly copy conversion results to clipboard after completion

Keyboard Shortcuts

Use Ctrl+Enter to quickly execute conversion operations

Character Statistics

Real-time display of input text character count

Format Preservation

Maintain original spaces, line breaks and other formatting during conversion

How to Use

Complete text case conversion in just three simple steps

1

Select Mode

Choose "uppercase to lowercase" or "lowercase to uppercase"

2

Input Text

Enter the text you want to convert in the input box

3

Get Result

Real-time display of results, click copy button to use

Frequently Asked Questions

Frequently asked questions about the case converter

What characters does this case converter support?

Our converter supports case conversion for all English letters (A-Z, a-z). Numbers, punctuation, spaces and line breaks remain unchanged to preserve text formatting. Unicode characters are supported, but only English letters undergo case conversion.

Is there a character limit for conversion?

There is no strict character limit. Our tool can handle conversion needs from a few characters to large text blocks, all processing is done locally in your browser ensuring performance and security. We recommend processing under 1 million characters at once for optimal performance.

Does it support batch text conversion?

Yes, you can input multi-line text for conversion at once. The tool maintains original line breaks and formatting, suitable for processing lists, code snippets and other multi-line text. Supports various formats like tab-separated, comma-separated text processing.

How to save converted text?

You can use the 'Copy' button to copy conversion results to clipboard, then paste anywhere needed. We also support direct selection of output text for copying. All operations are performed locally without uploading to servers.

Is this tool free?

Completely free! Our case converter requires no registration, has no usage limits, and provides service permanently free. We commit to keeping core features free for all users to access text processing tools conveniently.

How secure is my data with this tool?

Your data security is our top priority. All text conversion happens locally in your browser - we never collect, store, or transmit any of your text content. Your privacy and data are completely protected.

Which browsers are supported?

Our tool supports all modern browsers including Chrome, Firefox, Safari, Edge, and more. We recommend using the latest browser versions for the best experience. Mobile browsers are fully supported as well.

Are keyboard shortcuts supported?

Yes, multiple keyboard shortcuts are supported: Ctrl+Enter for quick conversion, Ctrl+A to select all text, Ctrl+C to copy results, Esc to clear input. These shortcuts greatly improve your workflow efficiency.

How are special characters and symbols handled?

Special characters, numbers, spaces, punctuation, line breaks, and other non-English letter characters remain unchanged during conversion. This ensures that code, URLs, email addresses, and other specially formatted text remain valid after conversion.

Can the tool remember my conversion history?

For privacy protection, we don't save your conversion history. Input and output fields are automatically cleared after each page refresh. Please copy results promptly to where you need them.

Does the tool work offline?

Yes! Since all conversion processing happens locally in your browser, you can use the tool offline after the page loads. This makes the tool reliable even in unstable network environments.

What if conversion results seem incorrect?

If you encounter conversion issues, try: 1) Refresh the page and retry; 2) Check if input text contains special encoding; 3) Process long text in segments; 4) Test with different browsers. If problems persist, report through our feedback channels.

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