Leet Speak Translator
Convert English to leet speak—or decode l33t back to readable text—with transparent, customizable rules.
Everything runs locally in your browser. Your text is never uploaded.How Leet Speak Translation Works
Leet speak—also written l33t or 1337—is a writing style that replaces letters with numbers or symbols that look similar. It started in 1980s online communities and is still common in gaming handles, screen names, and stylized messages.
This translator does not use a language model. Output comes from a fixed, visible character mapping that you can inspect and edit on this page. The same input, mode, and rules always produce the same output.
The three modes
- Light — only the most common substitutions (such as
a → 4,e → 3). Output stays very readable. - Classic — the standard 1337 alphabet. Balanced between style and readability.
- Extreme — letters become multi-character ASCII art (such as
m → |\/|). Maximum stylization, harder to read, and harder to decode.
Encoding and decoding
- Encoding replaces each letter once. It does not re-process the characters it just created, so output is stable.
- Decoding is rule-based best-effort. It matches the longest possible token first, so
|\/|correctly becomesminstead of three separate symbols. - Because several letters can map to the same character (for example, both
iandlmap to1in Classic mode), some leet text cannot be restored perfectly. The tool returns the most likely reading based on the current mapping. - Uppercase letters that have no mapping pass through unchanged, so
CatbecomesC47in Classic mode.
Custom rules
Open the character mapping below to edit any substitution. Your edits apply instantly and only live in this browser session. Use Reset to preset to restore the default mapping for the current mode.
Examples
Click any example to load it. The default mode is Classic—switch to Extreme to see multi-character replacements.
Character Mapping Table
The complete rule set for the current mode. Editing a cell updates every conversion immediately. These are the rules used by this site, not a universal standard.
View & edit mapping
| Letter | Becomes |
|---|
FAQ
What is leet speak?
Leet speak, also written as l33t or 1337, is a style of writing that replaces letters with numbers or symbols that look similar. It began in 1980s online and hacker communities and is still used today in gaming handles, screen names, and stylized text.
How does leet speak translation work?
Leet speak translation uses visible character-mapping rules. Letters are replaced with similar-looking numbers or symbols, so leet may become 1337. Light, Classic, and Extreme modes use progressively stronger substitutions, and the same input and rules always produce the same output.
Why is leet speak decoding imperfect?
Leet decoding is inherently ambiguous because one symbol can represent several letters—for example, 1 can mean both i and l. You can still translate leet speak back to English with Swap; the decoder matches longer tokens first and defaults 1 to l. The result is rule-based best-effort, not a guaranteed perfect reversal.
What is the difference between Light, Classic, and Extreme mode?
Light uses a small set of common substitutions and stays very readable. Classic covers the standard 1337 alphabet. Extreme replaces letters with multi-character ASCII art for maximum stylization. Higher modes are harder to read and harder to decode accurately.
Is my text uploaded or stored?
No. All conversion happens locally in your browser. Your text is never sent to a server and is not stored. You can verify this in your browser's network tab while typing—no requests are made as you type.