Uppercase Converter

When uppercase changes the length or the meaning

Uppercasing isn't always one letter in, one letter out. Keep these in mind when you store, compare or count the result:

• ß becomes SS, so Straße (6 characters) turns into STRASSE (7). If a field has a limit, recount with the Word Counter.
• Ligatures split into separate letters: the single character fi in fix becomes FI, giving FIX.
• Turkish has a dotted capital İ. The default rules turn istanbul into ISTANBUL, and Turkish text needs toLocaleUpperCase("tr") to get İSTANBUL. Use the default rules for identifiers, though, or title becomes TİTLE on a Turkish system.
• There's no way back. Lowercasing STRASSE gives strasse, not straße, so keep the original if you'll need it later.

Where capitals are the convention

In code and data, capital letters often carry meaning. These are the places you'll see them:

• CONSTANT_CASE, also called SCREAMING_SNAKE_CASE, for constants: MAX_RETRY_COUNT in JavaScript, Java and C, and in Python following the PEP 8 style guide.
• Environment variables such as DATABASE_URL and NODE_ENV. POSIX says the variables used by standard utilities contain only capital letters, digits and underscores.
• PascalCase for classes, types and React components. React needs that capital: a JSX tag that starts with a small letter, like <userCard />, is treated as a built-in HTML element.
• Acronyms inside PascalCase count as one word, so XMLHttpRequest becomes XmlHttpRequest. That matches the .NET naming guidelines, which capitalize only the first letter of acronyms longer than two letters.
• Standard codes: ISO country codes (PK, BR, JP), currency codes (USD, EUR, INR), IATA airport codes (DXB, LHR) and HTTP methods (GET, POST).
• SQL keywords like SELECT and WHERE, written in capitals by habit. The database itself doesn't care.
• Hashtags: #WorldBookDay is easier to read than #worldbookday, and screen readers say the words separately. The PascalCase button builds it from world book day.

All caps in writing, and the CSS alternative

Whole sentences in capitals read as shouting in email and chat; RFC 1855, the netiquette guidelines from 1995, already said so. Long passages in capitals are also slower to read, and some screen readers spell short all-caps words letter by letter, as if they were acronyms. Keep capitals for short labels, codes and the odd word of emphasis. For headlines, title case is usually the better choice, and the Title Case Converter applies it for you.

On a web page, if a button or a small heading only needs to look uppercase, keep normal case in the HTML and add text-transform: uppercase; in CSS, as in the last code tab. The content stays in normal case, so a later redesign doesn't mean rewriting text. Word's All Caps formatting works the same way: the letters only look like capitals.

Uppercase text in code

Here's the same conversion in code. Look closely at PHP and SQLite: their older functions skip accented letters and ß.

"Hello world".toUpperCase();             // 'HELLO WORLD'
"istanbul".toLocaleUpperCase("tr");      // 'İSTANBUL' (Turkish rules)

"Straße".upper()           # 'STRASSE'

mb_strtoupper("café straße");   // "CAFÉ STRASSE"
strtoupper("café straße");      // "CAFé STRAßE": only a to z change

"Straße café".upcase       # "STRASSE CAFÉ"

"Hello world".toUpperCase(Locale.ROOT)

"Hello world".ToUpperInvariant()

strings.ToUpper("Hello world")

SELECT UPPER(country_code) FROM orders;
-- SQLite's built-in UPPER() changes only a to z: 'straße' gives 'STRAßE'

echo "Hello world" | tr '[:lower:]' '[:upper:]'

name="Hello world"
echo "${name^^}"           # Bash 4 or newer

.button-label {
  text-transform: uppercase;
}