{"id":99,"date":"2026-05-04T21:40:27","date_gmt":"2026-05-04T21:40:27","guid":{"rendered":"https:\/\/simpletool.io\/blog\/?p=99"},"modified":"2026-05-04T23:02:14","modified_gmt":"2026-05-05T03:02:14","slug":"case-converter","status":"publish","type":"post","link":"https:\/\/simpletool.io\/blog\/case-converter\/","title":{"rendered":"Case Converter: Switch Text Between 12 Cases [2026]"},"content":{"rendered":"
TL;DR:<\/strong> A case converter switches text between UPPERCASE, lowercase, Title Case, Sentence case, and 8+ programming cases (camelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE, dot.case, path\/case, Train-Case). Our free case converter<\/a> handles all 12 in your browser, preserves Unicode (accented characters, emoji, non-Latin scripts), and copies output with one click.<\/div>\n

Switching letter case is the kind of micro-task that interrupts every writer and developer about a dozen times a week. You paste a tweet that came back UPPERCASE FROM A SCREAMING REPLY and need it back to sentence case. You name a CSS file and need my-component-styles.css<\/code> instead of MyComponentStyles.css<\/code>. You copy a section heading from a PDF that arrived in InCoNsiStEnT mIxEd CaSe<\/em>. Word and Google Docs handle the basics (Shift+F3 in Word; Format \u2192 Text \u2192 Capitalization in Docs), but neither covers the programming cases developers reach for daily.<\/p>\n

Our case converter<\/a> handles 12 case types in one tool, runs entirely in your browser, and gets the edge cases right (locale-aware Turkish dotted-I, ligatures, accented characters, mixed-script content). This guide explains every case, when to use which, the gotchas the obvious tools miss, and the keyboard-shortcut alternatives that fail on programming cases.<\/p>\n

All 12 case types and when to use each<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Case<\/th>\nExample<\/th>\nWhen to use<\/th>\n<\/tr>\n<\/thead>\n
UPPERCASE<\/strong><\/td>\nHELLO WORLD<\/code><\/td>\nHeadings in caps style guides, acronyms, SQL keywords<\/td>\n<\/tr>\n
lowercase<\/strong><\/td>\nhello world<\/code><\/td>\nEmail addresses, URLs, hashtags, casual UI labels<\/td>\n<\/tr>\n
Title Case<\/strong><\/td>\nHello World From Mars<\/code><\/td>\nHeadings in AP\/Chicago style; book and article titles<\/td>\n<\/tr>\n
Sentence case<\/strong><\/td>\nHello world from mars<\/code><\/td>\nModern UI copy (Google, GitHub, Apple HIG since 2015)<\/td>\n<\/tr>\n
camelCase<\/strong><\/td>\nhelloWorldFromMars<\/code><\/td>\nJavaScript variables, JSON keys, Java methods<\/td>\n<\/tr>\n
PascalCase<\/strong><\/td>\nHelloWorldFromMars<\/code><\/td>\nClass names (TypeScript, C#, Python), React components<\/td>\n<\/tr>\n
snake_case<\/strong><\/td>\nhello_world_from_mars<\/code><\/td>\nPython variables, Ruby methods, PostgreSQL columns<\/td>\n<\/tr>\n
CONSTANT_CASE<\/strong><\/td>\nHELLO_WORLD_FROM_MARS<\/code><\/td>\nEnvironment variables, language constants, enums<\/td>\n<\/tr>\n
kebab-case<\/strong><\/td>\nhello-world-from-mars<\/code><\/td>\nURLs, CSS class names, npm packages, file names<\/td>\n<\/tr>\n
Train-Case<\/strong><\/td>\nHello-World-From-Mars<\/code><\/td>\nHTTP headers (Content-Type<\/code>, X-Forwarded-For<\/code>)<\/td>\n<\/tr>\n
dot.case<\/strong><\/td>\nhello.world.from.mars<\/code><\/td>\ni18n keys, Java packages, namespaced configs<\/td>\n<\/tr>\n
iNVERSE cASE<\/strong><\/td>\nhELLO wORLD FROM mARS<\/code><\/td>\nFixing a CapsLock-on paragraph; novelty effect<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Title Case is the most misunderstood case<\/h2>\n

Title Case looks simple \u2014 capitalise the important words \u2014 but the major style guides disagree on which words count. AP Style capitalises words of 4+ letters; Chicago Style capitalises 5+ letters and treats is<\/em>, be<\/em>, are<\/em> as significant; APA Style capitalises any word longer than 3 letters; MLA Style capitalises the first and last word regardless of length, plus all major words. The result: the same headline can be valid Title Case under one guide and incorrect under another.<\/p>\n

Our converter follows AP Style by default (the most common guide for web headlines and blog posts) and lowercases articles (a<\/em>, an<\/em>, the<\/em>), short prepositions (at<\/em>, by<\/em>, in<\/em>, of<\/em>, on<\/em>, to<\/em>, up<\/em>), and short conjunctions (and<\/em>, but<\/em>, or<\/em>, nor<\/em>, for<\/em>, so<\/em>, yet<\/em>). The first and last word are always capitalised regardless. If you need Chicago or APA, use Title Case as a starting point and manually adjust the borderline words \u2014 typically 1-2 per headline.<\/p>\n

How to convert text case in your browser<\/h2>\n
    \n
  1. Open the case converter<\/a><\/li>\n
  2. Paste or type your text in the input box<\/li>\n
  3. Click any of the 12 case buttons \u2014 output appears instantly<\/li>\n
  4. Click Copy<\/strong> to copy to clipboard, or Download .txt<\/strong> for long text<\/li>\n
  5. Optional: tick the AP\/Chicago\/MLA selector for Title Case style preference<\/li>\n<\/ol>\n

    The Turkish dotted-I problem (and other Unicode gotchas)<\/h2>\n

    Naive case conversion (str.toUpperCase()<\/code> in JavaScript without a locale) breaks for Turkish and Azerbaijani. The Turkish alphabet has two distinct letters: I<\/code> (uppercase, no dot) and \u0130<\/code> (uppercase, with dot). Lowercase i<\/code> uppercases to \u0130<\/code>; lowercase \u0131<\/code> (dotless i) uppercases to I<\/code>. Default JavaScript ignores this and produces I<\/code> for both, corrupting Turkish text.<\/p>\n

    Our converter uses toLocaleUpperCase()<\/code> and toLocaleLowercase()<\/code> with an auto-detected locale, so istanbul<\/code> \u2192 \u0130STANBUL<\/code> in Turkish content (correct) rather than ISTANBUL<\/code> (wrong). Similar fixes apply to German \u00df<\/code> (uppercases to SS<\/code> in modern Unicode, or to \u1e9e<\/code> if you prefer the new capital eszett), Greek final sigma \u03c2<\/code> (lowercases differently from middle \u03c3<\/code>), and Lithuanian dotted letters.<\/p>\n

    Common gotchas<\/h2>\n