Leetspeak Converter
Convert text to leetspeak (1337) and decode it back, with basic, advanced and extreme alphabets.
Cheat sheet — Basic level
Leetspeak is a playful internet alphabet, not an encryption scheme — it offers no security
whatsoever. Decoding is best-effort: several letters share the same symbol (1 can be
i or l, 2 can be z or part of r), so a
decoded line may need a human eye.
How it works
Leetspeak (or "1337 5p34k") swaps letters for lookalike numbers and punctuation — a habit that
started on 1980s bulletin boards and stuck around in gamer tags, forum handles and passwords.
This converter runs three fixed substitution tables. Basic replaces only the
classic six (a→4, e→3, i→1, o→0, s→5, t→7), Advanced adds single-symbol
swaps for b, c, g, h, l and z, and Extreme uses a full ASCII-art alphabet
where every letter becomes a small drawing (l→|_, m→/\/\,
w→\/\/).
Switch the direction to translate leetspeak back into readable English: the decoder matches the longest symbol first, so multi-character shapes are recognised before single digits. Because the mapping is deliberately many-to-one, decoding is a best guess rather than a perfect round-trip. Everything happens in your browser with plain JavaScript — nothing you type is uploaded, logged or stored, and the tool keeps working offline.
Frequently asked questions
How do you write in leetspeak?
You swap letters for lookalike numbers and symbols. The classic six are a→4, e→3, i→1, o→0, s→5 and t→7, so "leet" becomes "l337". Advanced leet adds b→8, c→<, g→6, h→#, l→1 and z→2, and extreme leet draws every letter with punctuation, like l→|_ , m→/\/\ and w→\/\/.
What does 1337 mean?
1337 is leetspeak for "leet", short for "elite". It came from 1980s bulletin-board and hacker culture, where writing in substituted characters marked insiders and slipped past crude word filters. Today it mostly survives in gamer tags, forum handles and jokes.
Can this tool decode leetspeak back into normal text?
Yes — switch the direction to "Leetspeak → text" and the decoder matches the longest symbol first, so multi-character shapes are recognised before single digits. Because several letters share a symbol (1 can be i or l), decoding is a best guess and may need a quick human check.