Leetspeak (1337, "elite") is an informal writing system from 1980s bulletin boards and later online games in which letters are swapped for similar-looking digits and symbols: "leet" becomes "l33t", "hacker" becomes "h4x0r".

What do the numbers in leetspeak stand for?

The common substitutions are 4 or @ for A, 3 for E, 1 or ! for I and L, 0 for O, 5 or $ for S, 7 for T, 8 for B and 6 or 9 for G. Variants exist, which is why the same word can be written many ways.

Does leetspeak make a password stronger?

Barely. Password crackers apply the standard substitutions automatically, so "p4$w0rd" falls almost as quickly as "password". Length and randomness matter far more than symbol swaps.

Leetspeak Translator

Text to l33t and back.

About Leetspeak Translator

A leetspeak translator swaps letters for look-alike digits and symbols (e becomes 3, a becomes 4, t becomes 7) and can read 1337 text back into plain letters.

How to use

Type or paste plain text or leetspeak. Auto mode decodes when at least a quarter of the non-space characters are not letters; the switch at the top forces Text → Leet or Leet → Text.
The result appears as you type and has a Copy button.
In Text → Leet, every letter picks a random substitution from its list each time; Shuffle generates a different version of the same input.

What it supports

All 26 letters have between two and five substitutions, mixing digits (4, 3, 1, 0, 5, 7), ASCII art (|-| for h, |/| for m, // for w) and symbols (@, $, €, §).
Case is ignored on the way in; digits, spaces and punctuation pass through unchanged.
Decoding matches the longest known token first and maps it to one letter. Some tokens are ambiguous ("1" is both i and l, "6" is both b and g) and decode to one fixed choice, so round-tripping is not guaranteed.
Pure-letter substitutions such as "vv" and "em" are never decoded, so ordinary words inside leet text survive.

Example

elite hacker   → 3|_173 #4(|<3|2    (one random result)
h4ck3r l33t    → hacker leet

Privacy

Runs in the browser. No request is made, and nothing is stored.

Frequently asked questions

What is leetspeak?: Leetspeak (1337, "elite") is an informal writing system from 1980s bulletin boards and later online games in which letters are swapped for similar-looking digits and symbols: "leet" becomes "l33t", "hacker" becomes "h4x0r".
What do the numbers in leetspeak stand for?: The common substitutions are 4 or @ for A, 3 for E, 1 or ! for I and L, 0 for O, 5 or $ for S, 7 for T, 8 for B and 6 or 9 for G. Variants exist, which is why the same word can be written many ways.
Does leetspeak make a password stronger?: Barely. Password crackers apply the standard substitutions automatically, so "p4$w0rd" falls almost as quickly as "password". Length and randomness matter far more than symbol swaps.

Encode & decode

GUID Generator: One or many UUIDs, version 4 or 7.
ULID Generator: Sortable 26-character IDs with a time prefix.
Password Generator: Random passwords with length and character-set controls.
Hash Generator: MD5, SHA-1, SHA-256, SHA-384, SHA-512 and HMAC for text or a file.
Base64 Encoder / Decoder: Base64, Base32 and Base58 in both directions.
ROT13 / Caesar Cipher: Shift letters by any amount, or ROT13 in one click.
JWT Decoder: Read a token’s header and payload without sending it anywhere.
URL Encoder / Decoder: Percent-encode text for URLs, or decode it back.
HTML Entities: Escape &, < and > for HTML, or unescape them.
Base64 Image Encoder: Image to a Base64 data URL for CSS or HTML, or decode one back.
Random Number Generator: Random integers in a range, one or many, with or without repeats.
Bcrypt Generator: Hash a password with bcrypt, or check one against a hash.
AES Encrypt / Decrypt: Encrypt text with a passphrase using AES-256-GCM, or decrypt it.
Morse Code Translator: Text to dots and dashes, and back.

Data formats

XML ⇄ JSON: Convert between XML and JSON, from text or a file.
YAML ⇄ JSON: Convert between YAML and JSON, from text or a file.
CSV ⇄ JSON: Convert between CSV and JSON, from text or a file.
JSON to TypeScript: Infer TypeScript interfaces from a JSON sample.
JSON to Python Dataclass: Infer Python dataclasses from a JSON sample.
JSON to Pydantic Model: Infer Pydantic models from a JSON sample.
JSON to Go Struct: Infer Go structs with json tags from a JSON sample.
JSON to Rust Struct: Infer Rust structs with serde derives from a JSON sample.
JSON to Kotlin: Infer Kotlin data classes from a JSON sample.
JSON to C# Class: Infer C# classes from a JSON sample.
Base Number Converter: Binary, octal, decimal, hex and any base up to 36.
Text ⇄ Binary / Hex: Text to binary, hex, octal or decimal, and back.
Unix ⇄ UTC: Epoch seconds or milliseconds to a readable date, and back.
Timezone Converter: Convert a time between cities, with DST handled.
Cron Converter: Describe a schedule in words and get the cron expression.
Cron Expression Parser: Explain a cron expression in words and list its next run times.
Days Between Dates: The exact time between two dates, in days, weeks, months and years.
Age Calculator: Exact age in years, months and days, and the next birthday.
Epoch Clock: The current Unix timestamp, live, in seconds and milliseconds.
CIDR / Subnet Calculator: Network, broadcast, mask and host count for an IPv4 CIDR block.
Chmod Calculator: File permissions as octal (755) or symbolic (rwxr-xr-x).

Units & measures

Angle: Degrees, radians, gradians and turns.
Area: Square metres, feet, acres and hectares.
Bits / Bytes: Bits, bytes and every prefix up to petabytes.
Energy: Joules, calories, kilowatt-hours and BTU.
Frequency: Hertz, kilohertz, megahertz and RPM.
Fuel Economy: Miles per gallon, km per litre and litres per 100 km.
Length: Metres, feet, miles, inches and nautical miles.
Power: Watts, kilowatts and horsepower.
Pressure: Pascals, bar, PSI and atmospheres.
Speed: km/h, mph, knots and metres per second.
Temperature: Celsius, Fahrenheit and Kelvin.
Time Unit: Seconds, minutes, hours, days and beyond.
Volume: Litres, gallons, pints and cubic metres.
Weight: Kilograms, pounds, ounces and stone.

Text & code

Lorem Ipsum Generator: Placeholder paragraphs, sentences or words.
Slug Generator: Turn a title into a URL-safe slug.
Text Compare: Diff by line, word or character, unified or side by side.
URL Parser: Break a URL into host, path, query and fragment.
JSON Formatter & Validator: Validate, pretty-print or minify JSON.
JSON Diff: Compare two JSON documents, ignoring key order and formatting.
JSONPath Tester: Query JSON with a JSONPath expression.
SQL Formatter: Format and indent SQL for any dialect.
JavaScript Beautifier: Format minified or messy JavaScript into readable code.
HTML Formatter: Indent and tidy HTML, or strip it down to one line.
XML Formatter: Pretty-print or minify XML, with error positions.
CSS Minifier / Beautifier: Minify CSS, or expand it back to readable rules.
HTML to Markdown: Convert HTML to clean Markdown.
Text Case Converter: camelCase, snake_case, kebab-case, Title Case and more.
Markdown Previewer: Render Markdown as you type.
Whitespace Remover: Strip line breaks, extra spaces or both.
Sort Lines: Sort lines alphabetically, numerically, by length or reversed.
Duplicate Line Remover: Keep each line once.
String Counter: Characters, words, lines and bytes.
Regex Tester: Test a pattern against text with live matches.
Regex Cheatsheet: Regular-expression syntax with examples.

Word play

Palindrome Checker: Does it read the same backwards?
String Reverser / Rotator: Reverse a string or rotate it by n characters.
Roman Numeral Converter: 1984 ⇄ MCMLXXXIV.
NATO Phonetic Alphabet: Spell text out as Alfa, Bravo, Charlie.
Pig Latin Converter: English to Pig Latin and back.
Numeronym Generator: internationalization → i18n.
Leetspeak Translator: Text to l33t and back.
Word Frequency Counter: Which words appear most, and how often.

Images & colour

QR Code Generator: QR codes for text, links, Wi-Fi and contacts.
Barcode Generator: EAN, UPC, Code 128 and more as SVG or PNG.
Barcode / QR Reader: Decode a barcode or QR code from an image.
Color Picker: Pick a colour and copy it in every format.
Image Converter: Convert between PNG, JPEG and WebP, and resize on the way.
Contrast Checker: Contrast ratio of text on a background, against WCAG AA and AAA.
Favicon Generator: Every favicon size from one image.
Image Compressor: Shrink a JPEG, PNG or WebP in the browser.
Gradient Generator: Build a CSS gradient and copy the rule.
Box Shadow Generator: Tune a shadow and copy the CSS.

Reference

ASCII Table: Every ASCII character with its decimal, hex, octal, binary and HTML code.
HTTP Status Codes: Every HTTP status code with what it means and when to use it.
MIME Types: Common MIME types by file extension, searchable.
Port Numbers: Well-known and registered TCP and UDP ports and the services behind them.