Case Converter

Tool Overview

This tool converts text between many case styles. You paste or type your text and pick one style. The tool turns your text into that style at once. You can choose sentence case, all lower, all upper, title case, capitalized case, camelCase, PascalCase, snake_case, kebab-case, alternating case, or inverse case. So one block of text can be turned into the form you need for a heading, a variable name, a URL slug, or something else.

Different places need different case. A title might use Title Case. Code often uses camelCase or snake_case. A URL might use kebab-case. Doing it by hand is slow and easy to get wrong. This tool applies the chosen style to the whole block. You can turn on an option to keep acronyms in title case and you can highlight what changed so you see the result clearly.

The tool is for writers, editors, and developers. You do not need technical skills for basic styles. For programming styles like camelCase or snake_case it helps to know what they mean. An optional smart convert sends your text to a remote service and replaces it with a suggested version; the main conversion does not depend on it.

Background & Concept Explanation

Case means whether letters are uppercase or lowercase. Sentence case means the first letter of each sentence is capital. Title case means important words are capital. Lower case means all small letters. Upper case means all capitals. Programming and writing use more styles. camelCase runs words together with the first word lower and the rest with a capital start. PascalCase is like that but the first letter is also capital. snake_case uses underscores between words and is usually all lower. kebab-case uses hyphens between words and is usually all lower. Alternating case switches letter by letter between upper and lower. Inverse case flips each letter from upper to lower or lower to upper. A related operation involves converting speed units as part of a similar workflow.

Each style has a purpose. Sentence case is common in normal text. Title case is used for headings. camelCase and PascalCase are used for variable and class names in code. snake_case is used for file names and some identifiers. kebab-case is used in URLs and some config keys. Converting by hand you might miss a word or break a variable name. This tool applies the rules for the style you choose so the result is consistent.

People struggle when they do it manually. They forget which words to capitalize in title case. They mix up camelCase and PascalCase. They leave spaces in snake_case or use the wrong separator. This tool runs the conversion in one go. You pick the style and read the result. You can turn on highlight changes to see which parts changed. An optional smart convert can suggest a cleaned or improved version; that step can fail and the main conversion still works.

Key Features

• You paste or type text in an input area. The input is limited to 10000 characters. A counter shows how many characters you have and the maximum. When you are close to the limit the counter turns red. If you try to paste or type past the limit the tool shows a message and does not add the extra text. So the tool stays responsive.
• Twelve case styles are available. You pick one by clicking its button. Sentence case capitalizes the first letter of each sentence. Lower case converts all characters to lowercase. Upper case converts all to uppercase. Title case capitalizes principal words and keeps small words like a, the, and of in lowercase in the middle (APA style). Capitalized case capitalizes the first letter of every word. camelCase runs words together with the first word lowercase and the rest with a capital start. PascalCase is like camelCase but the first letter is also uppercase. snake_case converts to lowercase with underscores between words and removes other non letter non digit characters. kebab-case is similar but uses hyphens. Alternating case switches each letter between upper and lower. Inverse case swaps uppercase and lowercase for each letter. So you get the style you need in one click.
• A Preserve Acronyms checkbox affects title case. When it is on, words that are all capitals (like API or HTML) stay in capitals in the output. When it is off they are treated like normal words. So you can keep acronyms in titles.
• The output appears in a second panel. It updates as you type or when you change the style or options. You can scroll the input and the output scrolls in sync. A Highlight Changes checkbox toggles whether the output shows only the converted text or the same text with changed parts highlighted. So you see the result or you see what the tool changed.
• Copy copies the converted text to the clipboard. Clear empties the input and puts focus back in the input. So you can reuse the result or start over.
• Smart Convert is optional. When you have text in the input you can click it. The tool sends your text to a remote service. The service may return a revised version. That version replaces your input so you can then apply any case style to it. This step can fail; the main conversion does not depend on it.

Common Use Cases

You have a heading or title and need it in title case. You paste it, choose Title Case, and copy the result. Small words in the middle stay lowercase. Turn on Preserve Acronyms if you have terms like API that should stay in capitals. For adjacent tasks, converting length units addresses a complementary step.

You have a phrase or label and need it as a variable name. You paste it, choose camelCase or PascalCase, and copy. The tool splits on spaces and other separators, lowercases the words, and joins them with the right capitalization. Leading numbers are kept in camelCase.

You have a title or name and need it for a URL or a file name. You choose kebab-case or snake_case. The tool lowercases, replaces spaces with hyphens or underscores, and strips other characters. You copy the result and use it in the URL or file name.

You have mixed case text and want to see it in sentence case or all caps or all lower. You pick Sentence case, UPPER CASE, or lower case and copy. You can use Highlight Changes to see what changed before copying. When working with related formats, converting Roman numerals can be a useful part of the process.

You want a quick fix or suggestion for your text before converting. You click Smart Convert. If the service returns text it becomes the new input and you can then pick a case style. If it fails you still have your original input and can convert it manually.

How to Use This Tool

1. Open the case converter in your browser.
2. Paste or type your text in the input area on the left. The text must be 10000 characters or less. Watch the character counter; when you are near the limit it turns red. Pasting text that would go over the limit is blocked and a message appears.
3. Click one of the case style buttons at the top to choose the output style. The options are Sentence case, lower case, UPPER CASE, Title Case, Capitalized Case, camelCase, PascalCase, snake_case, kebab-case, aLtErNaTiNg cAsE, and iNVERSE cASE. The output on the right updates at once.
4. Optionally turn on Preserve Acronyms if you use Title Case and want words like API or HTML to stay in capitals. Optionally turn on Highlight Changes to see which parts of the output were changed from the input.
5. Read the output on the right. Scroll if needed; the output scrolls with the input. Copy the result with the Copy button when you need it elsewhere. Use Clear to empty the input and start over.
6. Optionally click Smart Convert to send your input to a remote service. Wait for the result. If the service returns text it replaces the input and you can then pick a case style and copy. If you see an error the conversion still works on your current input.

Calculations & Logic

Sentence case: the text is lowercased. The first letter after any leading spaces, numbers, or symbols is capitalized. After each run of sentence ending punctuation (period, exclamation, question mark) followed by space or newline, the next letter is capitalized. After a closing quote followed by such punctuation and space, the next letter is capitalized. A standalone letter i (as a word) is turned into I. So each sentence starts with a capital.

Title case: the text is split on spaces and on hyphen and dash characters. Each part is trimmed. If Preserve Acronyms is on, a word that is all uppercase letters is left as is. Otherwise a list of small words (a, an, and, as, at, but, by, for, if, in, nor, of, on, or, so, the, to, up, yet) is not capitalized when they appear in the middle of the title; the first and last word are capitalized. All other words get their first letter capitalized. The parts are joined back with the original separators. In some workflows, converting Julian dates is a relevant follow-up operation.

Capitalized case: the text is lowercased and then the first letter of each word (after a word boundary) is capitalized. camelCase: the text is trimmed and split on spaces, hyphens, underscores, and on boundaries where a lowercase letter meets an uppercase or where two capitals are followed by a lowercase. Each part is lowercased. The first part stays lowercase and each following part has its first letter capitalized. They are joined with no separator. Leading digits in the input are kept. PascalCase: the same as camelCase but the first character of the result is uppercased. snake_case: the text is lowercased, spaces become underscores, any character that is not a letter, digit, or underscore is removed, repeated underscores are collapsed, and leading or trailing underscores are removed. kebab-case: the same but with hyphens instead of underscores and only letters, digits, and hyphens kept. Alternating case: each letter in the text is toggled between upper and lower in order; non letters are unchanged. Inverse case: each uppercase letter becomes lowercase and each lowercase letter becomes uppercase; other characters are unchanged.

The highlight view splits the input and output by whitespace (keeping the spaces). Each segment of the output is compared to the segment at the same position in the input. If they differ the segment is marked as changed. For very long text the tool uses a character by character comparison so it stays fast.

If the input is longer than a safe length for processing, only the beginning of the text is converted. The input limit of 10000 characters keeps this from happening in normal use. For related processing needs, converting timestamps handles a complementary task.

Reference Tables or Scales

Limits:

Tips, Limitations & Best Practices

Choose the style that matches your use. For headings use Title Case or Sentence case. For code identifiers use camelCase or PascalCase. For URLs or file names use kebab-case or snake_case. Preserve Acronyms only affects Title Case; other styles do not use it.

Watch the character counter. If you paste a long document and hit the limit the extra part is not added. Split the text or trim it first. Smart Convert also has a length limit and can fail if the text is too long or the service is unavailable.

Use Highlight Changes to see what the tool changed. That helps you spot wrong splits or acronyms that were not preserved. You can then edit the input and convert again. For snake_case and kebab-case the tool removes characters that are not letters, digits, or the separator; so punctuation and symbols are stripped.

Smart Convert is optional and can fail. You may see an error about length or service. The main conversion does not depend on it. You can always convert with the chosen style and edit the result by hand if needed.

Clear empties the input only. It does not change the selected style or the checkboxes. So after clear you can paste new text and convert with the same settings.