Leet Speak (1337) Translator
Last reviewed on April 27, 2026.
Type a word or phrase and the tool replaces letters with the digit-and-symbol substitutions that came out of late-1990s bulletin-board culture. Three intensity levels: light for stylized but readable, classic for the familiar look most readers recognize, and extreme for full obfuscation.
What leet is and where it came from
Leet — short for elite — started as a way to type around naive keyword filters on early bulletin-board systems and IRC channels. By the late 1990s, the substitutions had stabilized into a small set of conventions: vowels became digits (A → 4, E → 3, I → 1, O → 0), then a few consonants joined (S → 5, T → 7, B → 8). Multi-character substitutions like K → |< and M → /\/\ came later and stayed niche because they break readability.
Today, leet survives as a stylization rather than a filter-evasion tactic. It signals "internet old-school" the way Comic Sans signals "informal" — instantly, and with a wink.
Three levels, three uses
Light
Only the vowels are replaced. Output stays readable to almost any audience, even people who have never seen leet before. Use this level for usernames you want to be both recognizable and stylized: cyberFox becomes cyb3rF0x, which still parses as a word.
Classic
The familiar set. About a third of the alphabet has a substitution. Readable to most internet-native audiences but enough to read as deliberate. This is the default and works for most stream overlays, video captions, and chat handles.
Extreme
Multi-character substitutions kick in. The text becomes unreadable to a casual reader and turns into a visual block rather than a word. Reserve this level for short, decorative phrases — taglines, transitions, single-frame captions — never for anything anyone has to read fast.
Worked example
Here is the same phrase, "system online", at each level, with random capitalization off:
| Level | Output |
|---|---|
| Light | syst3m 0nl1n3 |
| Classic | 5y57em 0nline |
| Extreme | $Y$73/\/\ 0/\/L1/\/3 |
Notice how readability collapses between classic and extreme. That collapse is the whole point — and the reason extreme should be used sparingly.
Where leet vs. glitch text vs. ASCII banner each fit
| Effect | Mechanism | Best for |
|---|---|---|
| Leet (this page) | Letter substitution | Usernames, taglines, anything that should still parse as words. |
| Glitch text | Unicode combining marks | Single-frame transitions and decorative beats; degrades platform-by-platform. |
| ASCII banner | Multi-row block letters | Headers, title cards, any context that needs a visual chunk rather than text. |
Common mistakes
- Leet inside passwords. The substitutions are predictable. A password manager and a strong passphrase beat any amount of
p455w0rd; the substitutions add maybe a couple of bits of entropy and a lot of typing friction. - Leet on important UI. A leet-styled menu label costs more in lost clicks than it gains in style. Reserve leet for handles, headers, and decoration.
- Mixed levels in the same string.
cyb3r5y57emreads as a typo, not a style choice. If you raise the level, raise it for the whole word. - Random capitalization on long strings. The randomization makes individual words harder to read. Keep it for short words or turn it off entirely for anything over five or six characters.
Pairs with other tools on this site
For a stylized version that still has letter shapes intact, run the result through the glitch text generator at chaos level 2 or 3. For a chunky title-card variant, drop the leet output into the ASCII banner generator — it preserves digits and most common substitution characters. For a frame around the result, use the box-drawing tool.