Capital Case Converter
Capitalize the first letter of every word, or convert text to UPPERCASE, lowercase, sentence case, camelCase, snake_case and other naming conventions as you type.
What is Capital Case?
Capital case, also called start case, capitalizes the first letter of every word and lowercases the rest: "the lord of the rings" becomes "The Lord Of The Rings". It applies one rule to every word, which makes it predictable. That's why it's common for button labels, product names and spreadsheet headers.
This converter handles a few cases that a simple "capitalize each word" rule gets wrong:
- Acronyms stay in capitals. "NASA launches a probe" becomes "NASA Launches A Probe", not "Nasa". If your whole input is in capitals, it's treated as shouting and converted normally.
- Apostrophes don't start new words. "don't stop" becomes "Don't Stop" and
dont_stop, notdon_t_stop. - Accented letters work. "élan vital" becomes "Élan Vital", and "café menu" becomes
café_menurather than losing the é. - Numbers aren't capitalized. "2nd place" stays "2nd Place", not "2Nd Place".
For the code naming conventions (camelCase, snake_case and so on), the tool first splits your text into words on spaces, punctuation and capital-letter boundaries, so pasting XMLHttpRequest gives you xml_http_request. It then rejoins those words using each convention's rules.
Capital Case vs Title Case vs Sentence Case
Capital case and title case are often confused. Capital case capitalizes every word. Title case follows a style guide that keeps short "minor" words lowercase, and the style guides disagree on which words count as minor. Here's the same headline under each rule:
| Style | Rule | Result |
|---|---|---|
| Capital case | Capitalize the first letter of every word | A Walk Through The Park Without Fear |
| Title case (AP, APA) | Capitalize major words and any word of four or more letters; lowercase short articles, conjunctions and prepositions | A Walk Through the Park Without Fear |
| Title case (Chicago, MLA) | Lowercase articles, prepositions and coordinating conjunctions regardless of length | A Walk through the Park without Fear |
| Sentence case | Capitalize only the first word and proper nouns | A walk through the park without fear |
"Through" and "without" are prepositions of four or more letters, so AP and APA capitalize them while Chicago and MLA don't. This tool produces capital case and sentence case. For a published headline, check which style guide your publication follows.
Every Case, Side by Side
The same two phrases run through all nine conventions, with where each one is typically used.
| Convention | "dark mode toggle" | "annual revenue report 2025" | Typical use |
|---|---|---|---|
| Capital Case | Dark Mode Toggle | Annual Revenue Report 2025 | Headings, button labels, names |
| UPPERCASE | DARK MODE TOGGLE | ANNUAL REVENUE REPORT 2025 | Acronyms, warnings, emphasis |
| lowercase | dark mode toggle | annual revenue report 2025 | Tags, email addresses, normalizing input |
| Sentence case | Dark mode toggle | Annual revenue report 2025 | Body text, UI messages, many style guides |
| camelCase | darkModeToggle | annualRevenueReport2025 | JavaScript and Java variables and functions |
| PascalCase | DarkModeToggle | AnnualRevenueReport2025 | Classes, types, React components |
| snake_case | dark_mode_toggle | annual_revenue_report_2025 | Python, Ruby, SQL column names |
| kebab-case | dark-mode-toggle | annual-revenue-report-2025 | URLs, CSS classes, file names |
| CONSTANT_CASE | DARK_MODE_TOGGLE | ANNUAL_REVENUE_REPORT_2025 | Constants and environment variables |
Notice the number in the second phrase stays attached to the word before it rather than moving to the end. It becomes its own segment in snake_case and kebab-case (report_2025, report-2025), and it's absorbed straight into the preceding word in camelCase and PascalCase (Report2025).
Practical Usage Examples
Spreadsheet Column Headers
Cleaning up headers exported in mixed or all-lowercase text:
"customer id, order date, SKU"Customer Id, Order Date, SKUJavaScript Variables
Converting a descriptive phrase to proper JavaScript naming:
"user login status"userLoginStatusconst userLoginStatus = true;Python Functions
Converting to Python's preferred naming convention:
"Calculate Total Price"calculate_total_pricedef calculate_total_price():URL Slugs
Creating readable URLs:
"How To Build A Website"how-to-build-a-websiteexample.com/blog/how-to-build-a-websiteFrequently Asked Questions
Is capital case the same as title case?
No. Capital case capitalizes every word, including 'a', 'of' and 'the'. Title case follows a style guide (AP, APA, Chicago or MLA) that keeps minor words like articles and short prepositions lowercase unless they start the title. See the comparison table above.
Why did my acronym stay in capitals?
Words that are already entirely in capitals, such as NASA, HTML or SKU, are treated as acronyms and left alone. If your whole input is in capitals, the tool assumes it's shouted text and converts every word normally.
Which case should I use for JavaScript?
Use camelCase for variables and functions (myVariable, getUserData), PascalCase for classes and components (MyComponent, UserModel), and CONSTANT_CASE for constants (MAX_SIZE, API_KEY).
What's the difference between camelCase and PascalCase?
camelCase starts with a lowercase letter (myVariable), while PascalCase starts with an uppercase letter (MyClass). PascalCase is also called UpperCamelCase.
Why use snake_case in Python?
Python's style guide, PEP 8, recommends lowercase words separated by underscores for function and variable names, and CapWords (PascalCase) for class names.
Should URLs use hyphens or underscores?
Hyphens. Google's URL guidelines recommend hyphens rather than underscores to separate words, so kebab-case is the usual choice for slugs.
How should acronyms be written in camelCase?
Style guides disagree. Google's Java and JavaScript guides treat acronyms as ordinary words (XmlHttpRequest, userId), while .NET keeps two-letter acronyms in capitals (IOStream). The browser's own XMLHttpRequest API keeps 'XML' in capitals. Pick one rule and apply it consistently in a codebase.
Should database columns use snake_case?
Usually, yes. Unquoted SQL identifiers are case-insensitive in most databases, and PostgreSQL folds them to lowercase, so camelCase names lose their humps unless you quote them every time. Hyphens aren't allowed in unquoted names either, which leaves snake_case (user_id, created_at) as the readable option.
How do I handle numbers in case conversions?
Numbers stay where they are. When a number is separated by a space it becomes its own word: 'user 2 profile' becomes user2Profile in camelCase and user_2_profile in snake_case. Most programming languages don't allow an identifier to start with a digit, so avoid leading numbers even though this tool won't stop you.
Sources
- APA Style: Title case capitalization
- The Chicago Manual of Style and the AP Stylebook: headline capitalization rules.
- PEP 8: Style Guide for Python Code
- Google Search Central: URL structure best practices
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