Generate example passwords that follow the common PCFG base structures - letters, digits, and symbols in the orders real people actually use - and see the structure notation (like L6D2S1) for each one. Pick a specific structure or sample them by real-world frequency, with a strong uniform-random mode included for real use. Everything runs in your browser.
PCFG Password Pattern Generator
This tool builds example passwords that follow the base structures a PCFG password-guessing model learns from real leaked password sets. Pick a structure like L6D2S1 - six letters, two digits, one symbol - or let the tool sample structures by how often they appear, then read the structure label printed beside each generated string.
A PCFG (probabilistic context-free grammar) treats every password as a sequence of character-class segments: L for a run of letters, D for digits, S for symbols. Guessing tools rank these structures by frequency and try the common ones first, which is why "monkey99!" (L6D2S1) falls far faster than its eight-character length suggests. Seeing your own habits written in the L/D/S notation is the quickest way to understand why a longer, patternless password wins.
Eight common base structures
The generator's reference table mirrors widely published analyses of leaked password corpora (rounded, illustrative shares - this tool does not measure a live dataset):
| Structure | What it means | Example | Share |
|---|---|---|---|
L | Letters only | sunshine | ~34% |
LD | Letters then digits | letmein123 | ~24% |
D | Digits only | 12345678 | ~16% |
LDS | Letters, digits, then symbol | monkey99! | ~7% |
LS | Letters then symbol | dragon! | ~5% |
DL | Digits then letters | 1qwerty | ~4% |
LDL | Word, digits, word | red7car | ~3% |
SLDS | Symbol-wrapped word | !tiger9# | ~2% |
Three ways to generate
- Sample common patterns by frequency - the tool picks a base structure weighted by its real-world share, so the mix of examples you see matches how guessing tools prioritize their attempts.
- Generate from one specific base structure - pick a row from the table above (say
LDS) and see several examples that all follow that exact letters-digits-symbol shape, filled with the common digit/symbol choices real people use (1,123,2024-2026,!,@). - Strong uniform-random password - every character is picked independently from a full letter/digit/symbol pool (ambiguous characters like
l/o/0/1removed), with an entropy-in-bits figure next to the result, for a password meant for real use.
Everything stays on your device
The generator runs entirely in your browser. Every character comes from the Web Crypto secure random generator, nothing is uploaded or logged, and no password is ever sent to a server or checked against any database. For a password you will actually use, switch to the strong uniform-random mode and store the result in a password manager.
Frequently Asked Questions
What is a PCFG base structure?
It is the shape of a password written as character-class segments: L for a run of letters, D for digits, S for symbols, with the number giving each segment's length. For example "monkey99!" is L6D2S1. A password-guessing model learns which structures are most common and tries those first.
Are the example passwords safe to use for my accounts?
No. The pattern examples deliberately follow common, guessable human structures so you can see how quickly a cracking model would reach them. For a real account, switch to the strong uniform-random mode, use at least 16 characters, and store the result in a password manager.
Does anything I generate leave my browser?
No. Every string is created locally with the Web Crypto secure random generator. Nothing is uploaded, logged, sent to a server, or checked against any breach database, so you can run it offline.