Leetspeak

Converts text to and from basic leetspeak.

Leetspeak converts text to and from basic 1337 (leet) using a small letter-to-number substitution. In encode mode it replaces a/e/i/o/s/t with 4/3/1/0/5/7, and in decode mode it reverses those numbers back to letters. It is handy for quick fun text styling, generating playful handles, or decoding simple leetspeak you come across.

Common uses

• Encode a username or display name into a leetspeak style for gaming or chat
• Decode short leetspeak strings back into readable text
• Generate playful headers or labels for a side project
• Quickly transform sample text when testing how mixed letters and digits render
• Show what a phrase looks like in classic 1337 substitution

FAQ

Is my data sent to a server?

No. The conversion runs entirely in your browser using local JavaScript, and nothing you type is uploaded or stored on any server.

Which characters does it convert?

Encoding maps a, e, i, o, s, and t to 4, 3, 1, 0, 5, and 7. Decoding maps 4, 3, 1, 0, 5, and 7 back to a, e, i, o, s, and t.

Is the conversion case sensitive?

Encoding lowercases each character before matching, so both uppercase and lowercase vowels and the supported letters are converted to the same digit.

Why is decoding not always identical to the original text?

Decoding only knows the six number-to-letter mappings, and encoding loses original casing. So decoding produces lowercase letters, and any digits in your original text that match the map will also be turned into letters.

Are characters that have no mapping changed?

No. Any character without a matching entry, such as punctuation, spaces, or unsupported letters, is passed through unchanged.

Related tools

• ASCII Art (Figlet)
• Deduplicate Lines
• Find & Replace
• Strip HTML Tags
• Remove Invisible Characters
• Morse Code
• Pad / Truncate Lines
• Reverse Text