Last updated October 13, 2026 · Report an error
Leet speak (also written "1337") replaces certain letters with visually similar numbers or symbols, and has been a fixture of internet and gaming culture since the early online forums and BBS communities.
This tool translates text into leet speak, or decodes leet speak back into regular text.
How it works
Choose a direction and enter your text. Converting to leet speak replaces certain letters with lookalike numbers or symbols (a→4, e→3, i→1, o→0, s→5, t→7, l→1, g→9, b→8); decoding reverses common substitutions back to letters.
- Enter mode.
- Enter text.
- Click Calculate to see your results.
Examples
Converting "leet"
"leet" converts to "1337" in leet speak.
Who should use it
- Adding a playful, internet-culture style to usernames or messages.
- Decoding leet speak text encountered online back into readable form.
Industry applications
- Gaming and internet culture
- Content and social media
Advantages
- Works in both directions from a single tool.
- Uses the most common, widely recognized substitution set.
Limitations
- Decoding is approximate due to ambiguous substitutions (like the number 1).
Common mistakes to avoid
- Expecting a perfect round-trip decode — because some substitutions are ambiguous (1 could be "i" or "l"), decoded text may not exactly match the original.
- Assuming leet speak has a single official standard — many variants and personal styles exist beyond this tool's common substitution set.
Best practices
- Use leet speak for informal, playful text — it's a stylistic choice rather than a formal encoding standard.
Tips
- For usernames or passwords using leet speak substitutions, remember that the substitutions are predictable — don't rely on leet speak alone to make a password meaningfully more secure.
Frequently asked questions
Yes, with no signup and no limit on how many translations you run.
Approximately — since some numbers (like "1") can represent more than one original letter (i or l), decoding is a best-effort reconstruction rather than a perfect guarantee of the original text.
It originated in early hacker and gaming online communities partly to bypass text filters and partly as an in-group style, and has since become a widely recognized piece of internet culture.
No — only letters with a common numeric or symbolic lookalike are substituted; the rest of the text (including uppercase letters, which keep their case) is left unchanged.