Leetspeak converter
Leetspeak, or 1337, replaces letters with numbers and symbols that look similar. Pick basic for digits only or advanced for symbols too, and see the mapping below. Decode mode reads it back as best it can.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose Text to leetspeak or Leetspeak to text.
- Choose Basic or Advanced and type your text. Copy the result.
The mapping
Basic: a=4, e=3, i=1, o=0, s=5, t=7.
Advanced: a=@, b=8, e=3, g=9, h=#, i=!, l=1, o=0, s=$, t=+, z=2.
Characters outside the table, digits and punctuation pass through untouched when encoding.
Worked example
“Leet speak” becomes “L337 5p34k” at the basic level and “133+ $p3@k” at the advanced level. Decoding “133+ $p3@k” at the advanced level gives “leet speak”.
Tips
Leetspeak began in online communities as a way to dodge word filters and look insider; today it is mostly style. Many spellings exist, so your favourite may differ from the table here. Decoding is a guess: always read the result.
Frequently asked questions
What are the two levels?
Basic replaces six letters with digits, a to 4, e to 3, i to 1, o to 0, s to 5 and t to 7. Advanced uses eleven, a to @, b to 8, e to 3, g to 9, h to #, i to !, l to 1, o to 0, s to $, t to + and z to 2. Capital and small letters get the same replacement; letters not in the table stay as they are.
Does it keep my capital letters?
Only for letters that are not replaced. A replaced letter becomes a digit or a symbol, which has no case, so "Leet" becomes "L337" in basic mode but the first letter is a capital only because L is not in that table.
How does decoding work, and when does it fail?
Each digit or symbol from the chosen table is turned back into its letter, and the result is lower case. To avoid damaging numbers, only words that contain at least one letter are decoded, so "2026" and "1+1" are left alone. For the same reason a word in which every letter was replaced, such as "1337" or "#3110", looks like a number and is not decoded. Symbols at the end of a word are kept, so "Hello!" is not changed to "Helloi". It can still go wrong: "1" is "i" in basic mode and "l" in advanced mode, and in advanced mode "R2D2" becomes "rzdz" and a hashtag like "#tag" loses its sign.
Is leetspeak a good way to make a password?
No. Common substitutions such as a to @ and o to 0 are the first thing password-guessing tools try, so they add almost no strength. Use a random generator instead.