Text case is one of those details that separates polished writing and clean code from sloppy work. Using UPPERCASE in a blog title or camelCase where snake_case belongs can undermine your credibility — whether you're a developer, content writer, or student. This guide covers every major text case type, when to use each, and the rules that govern them in writing, SEO, coding, and design.
There are more text cases than most people realise. Here is every major one with an example using the same phrase — "the quick brown fox":
Title case is more nuanced than simply capitalising every word. Different style guides (AP, Chicago, APA, MLA) have slightly different rules — but the core principles are consistent:
The universal Title Case rule: Capitalise all "major" words — nouns, verbs, adjectives, adverbs, and pronouns. Leave "minor" words lowercase — articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, so, yet), and short prepositions (in, on, at, to, by, of, up) — UNLESS they are the first or last word of the title.
| Word Type | Title Case Rule | Examples |
|---|---|---|
| Nouns | Always capitalise | India, Calculator, Income, Tax |
| Verbs | Always capitalise | Calculate, Build, Is, Are, Was |
| Adjectives & Adverbs | Always capitalise | Free, Better, Quickly, Best |
| Pronouns | Always capitalise | You, Your, It, They, We |
| Articles (a, an, the) | Lowercase (unless first/last word) | "A Guide to the Best Tools" |
| Short prepositions (in, on, at, of…) | Lowercase (unless first/last word) | "How to Save on Income Tax" |
| Coordinating conjunctions (and, but, or…) | Lowercase (unless first/last word) | "Buying and Selling in India" |
Sentence case capitalises only the first word of the sentence and any proper nouns. It reads exactly like a normal sentence — and it is increasingly the standard in modern digital product design.
Google's Material Design guidelines, Apple's Human Interface Guidelines, and Microsoft's Fluent Design system all recommend sentence case for UI elements — buttons, labels, menu items, and error messages. The reason: sentence case is easier to scan and feels less formal, which reduces cognitive load in interfaces.
In code, the choice of naming convention is not aesthetic — it is often enforced by language style guides and linters. Using the wrong case in code causes readability issues and fails code reviews.
| Case Type | Language / Context | Example | Standard Guide |
|---|---|---|---|
| camelCase | JavaScript variables & functions | getUserById() | Airbnb / Google JS Style |
| camelCase | Java variables & methods | calculateEmi() | Oracle Java Conventions |
| camelCase | Dart / Flutter variables | totalAmount | Dart Style Guide |
| PascalCase | React components | EmiCalculator | React Official Docs |
| PascalCase | Python classes | UserProfile | PEP 8 |
| PascalCase | C# all methods & classes | CalculateTax() | Microsoft .NET Guide |
| snake_case | Python variables & functions | total_tax_amount | PEP 8 |
| snake_case | Database column names | user_id, created_at | SQL conventions |
| kebab-case | CSS class names | .nav-bar, .hero-section | BEM / general CSS |
| kebab-case | URL slugs & HTML filenames | emi-calculator.html | W3C / SEO best practice |
| SCREAMING_SNAKE | Constants in Python & JS | MAX_RETRY_COUNT | PEP 8 / JS conventions |
| SCREAMING_SNAKE | Environment variables | DATABASE_URL | 12-Factor App standard |
Mixing conventions is a code smell. If a codebase uses getUserData in one file and get_user_data in another, it signals inconsistency. Most teams enforce conventions via linters (ESLint for JS, pylint for Python, dartfmt for Dart) — check your project's linting config before naming new variables.
Text case choices affect not just readability but SEO performance, CTR from search results, and brand perception.
Google treats URLs as case-sensitive — toolloom.in/EMI-Calculator and toolloom.in/emi-calculator are technically different URLs. Lowercase kebab-case is the universal standard: readable, safe, and consistent. Never use spaces or underscores in URLs — spaces encode as %20 and underscores make Google treat the words as one unit.
Title case performs slightly better for blog post titles in search results — it signals a polished, intentional headline. The ToolLoom convention: Title Case for H1 and meta title, sentence case for H2s and below. This balances authority (title case headline) with readability (sentence case subheadings).
Indian content writing tip: When writing for Indian audiences, avoid ALL CAPS headings — they read as aggressive in Indian digital communication norms. Title case or sentence case headings are warmer and more trustworthy for finance, health, and educational content.
| Situation | Recommended Case | Example |
|---|---|---|
| Blog / article H1 title | Title Case | How to Calculate Your Income Tax in India |
| H2 and H3 subheadings | Sentence case | Why your credit score matters |
| UI button labels | Sentence case | Save changes · Get started · Learn more |
| URL slugs | kebab-case | /tools/emi-calculator |
| JavaScript variable | camelCase | totalLoanAmount |
| Python variable / function | snake_case | total_loan_amount |
| React / class name | PascalCase | EmiCalculator |
| CSS class name | kebab-case | .nav-bar, .hero-section |
| Constant / env variable | SCREAMING_SNAKE | MAX_LOAN_AMOUNT, API_KEY |
| Acronym within sentence | UPPERCASE | GST, EMI, UPSC, NPS, CIBIL |
| Email subject line | Sentence case or Title Case | Your invoice is ready · How to Reduce Your EMI |
| Product / brand name | Title Case or PascalCase | ToolLoom, SBI YONO, PhonePe |
| Mistake | Why It's Wrong | Fix |
|---|---|---|
| Capitalising every word in subheadings | Over-formatted; Google style guides specifically recommend sentence case for subheadings in content | Use sentence case for H2, H3: "How to use the calculator" not "How To Use The Calculator" |
| Using underscores in URLs | Google treats underscored words as a single compound word — "emi_calculator" = "emicalculator" in index | Always use hyphens in URLs: /emi-calculator not /emi_calculator |
| ALL CAPS for long text passages | ALL CAPS is 10–20% slower to read than mixed case; perceived as shouting in digital communication | Reserve CAPS for acronyms, constants, and critical single-word warnings only |
| Using Title Case for UI button labels | "Save Changes", "Get Started" feel corporate and stiff; Google, Apple, and Material Design all mandate sentence case | Use sentence case: "Save changes", "Get started", "Try it free" |
| Mixing camelCase and snake_case in one codebase | Inconsistency signals poor code hygiene; fails linting checks; confuses team members | Agree on one convention per language at project start; enforce with a linter |
ToolLoom builds free writing, coding, and financial tools for Indian students, professionals, and creators. Found an error or want a new case format added? Email us at contact@toolloom.in