Leet speak translator
Turn any phrase into leet speak (1337) with two intensity levels, or paste leet text and decode it back on the fly.
What is leet speak (1337)?
Leet speak was born on the BBSes and forums of the '80s and '90s: the word "elite" became "leet" and then "1337", written by swapping letters for numbers and symbols that look alike. Originally it was a way to slip past automatic word filters; today it lives on mostly in gaming, in nicknames, and in usernames when the "normal" one is already taken.
One practical warning: using leet to "strengthen" a password (like p4ssw0rd) does not make it secure. Password-cracking tools automatically try every leet variant of common words, so those substitutions add essentially no protection.
How the conversion works (and its limits)
Level 1 applies the six classic substitutions (a→4, e→3, i→1, o→0, s→5, t→7) and stays readable to almost anyone. Level 2 adds b→8, g→9, z→2 and symbol combos like |-| for h or \/\/ for w: more dramatic, but harder on the eyes.
Decoding is best-effort: it turns numbers and symbols back into the most likely letters, but it can never be perfect. The digit 1, for example, always comes back as "i" even when it originally stood for an "l", and the digits of a real number (like a year) get turned into letters too. Always double-check the result before using it.