String Length Calculator Online - Count Characters, Words & Bytes

Multiple consecutive spaces, tabs, and newlines are treated as a single word boundary. "hello world" with three spaces still counts as two words. The word count is computed by splitting on one or more whitespace characters and filtering out empty strings, matching how most text editors and word processors count words.

JavaScript's .length counts UTF-16 code units, so most characters including CJK and simple emoji count as 1. However, some emoji composed of multiple code points with zero-width joiners (family emoji, skin-tone-modified emoji, flag sequences) may count as 2 or more. The byte count uses TextEncoder (UTF-8): ASCII = 1 byte, Latin-1 supplement = 2 bytes, CJK = 3 bytes, emoji = 4 bytes.

Sentences are detected by splitting on sentence-ending punctuation: period (.), question mark (?), and exclamation mark (!). Each resulting segment that contains at least one non-whitespace character is counted as a sentence. This is a heuristic approach — it does not handle abbreviations (e.g., "Dr.", "U.S.") or decimal numbers (e.g., "3.14") that contain periods.

Character count counts Unicode code points as JavaScript sees them (UTF-16 code units). Byte count uses UTF-8 encoding via TextEncoder. In UTF-8, ASCII letters are 1 byte, accented Latin characters are 2 bytes, Chinese/Japanese/Korean characters are 3 bytes, and emoji are 4 bytes. A 10-character Chinese string could be 30 bytes, while a 10-character ASCII string is only 10 bytes.

Yes — the byte count shown uses UTF-8 encoding, which matches how most web APIs and HTTP clients encode text. If you are building a JSON API, the byte count of the string value (excluding JSON syntax overhead like quotes and commas) is what the tool measures. For the full payload size including JSON structure, serialize the entire object and measure its length separately.

JavaScript's .length counts UTF-16 code units. For characters in the Basic Multilingual Plane (BMP), this is the same as the number of characters. However, for characters outside the BMP (like some emoji and rare CJK characters), JavaScript counts them as 2 because they use surrogate pairs. PHP's mb_strlen() with UTF-8 counts actual Unicode characters, giving a different result. For example, the emoji 😀 is 2 in JavaScript's .length but 1 in mb_strlen. Always specify the encoding when comparing string lengths across languages.

The ECMAScript specification limits string length to 2⁵³ - 1 elements (~9 quadrillion code units), but in practice the maximum depends on the browser and available memory. Most modern browsers can handle strings up to ~256 MB, which corresponds to roughly 256 million ASCII characters. For very large strings, operations become slow because JavaScript strings are immutable and copying requires O(n) memory. If you need to process large text, consider streaming or chunking the input.

For accurate Unicode character counts: In JavaScript, use [...str].length or Array.from(str).length instead of str.length. In Python, len(str) returns the correct Unicode character count. In PHP, use mb_strlen($str, 'UTF-8') instead of strlen(). In Go, utf8.RuneCountInString(str) gives the correct count. In Java, str.codePointCount(0, str.length()) handles surrogate pairs. The key insight: most language-native string length methods count code units, not visible characters. Use Unicode-aware APIs for accurate results.

In bash, the length of a string variable is obtained with ${#var}. For example: str="hello"; echo ${#str} prints 5. This counts characters, not bytes. For byte length, use echo -n "$str" | wc -c. Note that bash's ${#var} counts characters based on the current locale settings — for UTF-8 locales it correctly counts multi-byte characters as single characters. For POSIX-compatible behavior across all shells, pipe to wc -m for character count or wc -c for byte count.

In MySQL, VARCHAR(n) stores up to n characters (max 65,535 bytes total row limit) and uses 1-2 bytes overhead. TEXT stores up to 65,535 bytes (65KB) with 2 bytes overhead. In PostgreSQL, VARCHAR(n) stores up to n characters (no overhead), TEXT stores unlimited characters — functionally they are identical, with VARCHAR(n) adding a length constraint. In SQL Server, VARCHAR(n) max is 8,000 characters, and VARCHAR(MAX) stores up to 2GB. Use VARCHAR when you need a length constraint; use TEXT/VARCHAR(MAX) for arbitrarily long content. The actual string length in characters can be checked with LENGTH(column) (MySQL) or LEN(column) (SQL Server).