This pronounceable password generator builds passwords out of syllables rather than words, so you can read one down a phone line without spelling every character. None of them is a real word.
What is a pronounceable password generator?
A pronounceable password generator assembles random syllables into something sayable —Clonoloostofar rather than k3w9zq4mt. It has no dictionary: the syllables were never words, so there is nothing for an attacker to look up.
Syllables, not words
This site has three tools that produce something a person can handle. What separates a pronounceable password generator from the other two is where the randomness comes from.
- The passphrase generator draws from 7,776 real words.
- The memorable password generator draws from 1,296 short real words.
- This one draws from 285 syllables that are not words at all.
The trade shows up in length. Words are easy to recall and expensive in characters; syllables are harder to recall and much cheaper. A pronounceable password generator is the right pick only when the password has to leave your screen.
When it is the right choice
Any time the password has to travel through a human ear: reading a code to a colleague, dictating a temporary login over the phone, writing one on a whiteboard for a workshop. That is the whole case for a pronounceable password generator.
A random string forces you to spell out every character and confirm each one. A pronounceable password generator produces something you can say once.
The mistake this category is known for
The standard for it was withdrawn
NIST published FIPS 181, the Automated Password Generator, in 1993. Its abstract describes an algorithm that "randomly creates simple pronounceable syllables as passwords" — which is exactly what a pronounceable password generator does.
It was withdrawn on 19 October 2015, and nothing replaced it. The Perl moduleCrypt::GeneratePassword, one of the few implementations that engages with the question at all, says it avoids FIPS-181 "which is proven to be insecure", citing a 1994 paper by Ganesan and Davies.
Where the entropy goes
The failure is in how you pick. The tempting way to build a pronounceable password generator is to choose a pattern — consonant-vowel, or consonant-vowel-consonant — and then fill it in.
Patterns hold different numbers of passwords. Choosing between them evenly makes every password inside the small pattern far more likely than any inside the large one.
A single syllable can end open, with no final consonant, in 285 ways, or closed in 6,270 ways, for 6,555 possibilities in total. Choosing between the two shapes with an even coin and then filling the shape gives every open password a 0.175 percent chance and every closed one 0.008 percent, so the most likely password is twenty-two times more likely than the least. Its guessing resistance is 9.16 bits. Enumerating all 6,555 possibilities first and drawing once gives every password a 0.0153 percent chance and the full 12.68 bits.
An attacker who knows the shapes does not attack the average. They start with the cheap half, which is exactly the half a careless pronounceable password generator makes cheapest.
So this one never picks a shape
All 285 syllables are enumerated once, before anything is generated, and each draw takes one of them uniformly. This pronounceable password generator has no pattern decision to get wrong.
Constraints still apply — a vowel pair only follows a single consonant, becausesproo is not sayable — but they are applied while building the list, not while drawing from it. Ruling combinations out before enumeration is free; weighting them afterwards is the bug.
Which makes the entropy a count
Every syllable is consonants then vowels with no ending, so a finished password alternates consonant and vowel runs and can be split apart exactly one way. Five syllables and an ending is 285⁵ × 23 possibilities: 45.3 bits, counted rather than estimated.
What you pay for being sayable
Bits per character
Every readable password format buys legibility with entropy, and a pronounceable password generator is no exception. The useful question is the exchange rate.
Forty-five bits of entropy takes about nine characters as random letters and digits, fifteen as pronounceable syllables, twenty-four as short list words with separators, and twenty-eight as long list words with separators. Pronounceable syllables carry 3.06 bits per character, against 5.17 for fully random, 1.87 for the short word list and 1.62 for the long one.
A pronounceable password generator gives up about 40% of the density of a random string. It buys back roughly twice the density of a word-based password, which is why the output is so much shorter than a passphrase of the same strength.
How many syllables to take
Five is the default: 45 bits in about fifteen characters, which fits every password field and still chunks neatly when you say it. Fewer than four and a pronounceable password generator stops earning the entropy it gave up.
Seven gets you past 60 bits at around twenty-one characters, which is the setting to use for anything that will outlive the conversation it was read out in.
Why the digit sits at the end
The memorable password generator deliberately hides its digit inside a word, because cracking rules try trailing decorations first.
Here that would be self-defeating: nobody can read bak7lomi aloud. The digit and symbol go on the end, and because their position is predictable this pronounceable password generator does not count them toward the figure it shows you.
The words it refuses to say
Why a filter is needed at all
Let a pronounceable password generator assemble syllables for long enough and it will produce something you would not want to read out in an office. This is not a hypothetical risk.
The prototype for this page produced an unmistakable obscenity within its first dozen samples, which is what settled the question. About one draft in twenty-three contains something from a list of roughly sixty substrings.
Rejected, not repaired
A draft that trips the filter is thrown away and another drawn. It is never patched.
Changing a letter to break up an unwanted word would quietly bias the output: some syllables would start appearing more often than others, in a pattern nobody could see.
Discarding keeps every surviving password exactly as likely as every other, which is the same principle that makes this pronounceable password generator draw from an enumerated list in the first place.
What the filter costs
Removing about 4.3% of the space costs 0.066 bits out of 45.3. That figure is measured over twenty thousand draws rather than assumed.
The measurement is the point: a filter that quietly removed a large share would be reshaping what the pronounceable password generator produces, not trimming it, and nobody would be able to tell from the output.
Frequently asked questions
Are these real words?
No, and deliberately not. There is no dictionary anywhere in this generator — every password is assembled from 285 syllables that were never words. That matters because a password built out of real words is only as hard to guess as the list it came from, and an attacker knows the common lists.
How is the entropy figure calculated?
By counting, not estimating. The syllables are enumerated once and drawn uniformly, and because every syllable is consonants-then-vowels the letters alternate in runs, so a finished password can only be split apart one way. Five syllables plus an ending is 285⁵ × 23 possibilities, which is 45.3 bits exactly.
Why not use FIPS 181, the NIST standard for this?
Because NIST withdrew it on 19 October 2015 and named no replacement. The Perl module Crypt::GeneratePassword, one of the few implementations that discusses the question, states plainly that it avoids FIPS-181 "which is proven to be insecure", citing a 1994 paper by Ganesan and Davies.
What is wrong with picking a pattern and filling it in?
Patterns hold different numbers of passwords. Choose evenly between a short one and a long one and every password inside the short pattern becomes far likelier, so an attacker starts there. For a single syllable that drops the resistance from 12.68 bits to 9.16. This pronounceable password generator draws once from a finished list instead.
How strong is a pronounceable password compared with a random one?
Weaker per character and stronger per character than words. Syllables carry about 3.06 bits per character against 5.17 for fully random letters and digits, and 1.62 to 1.87 for word-based passwords. Forty-five bits takes 9 random characters, 15 pronounceable ones, or 24 to 28 with words.
Why is the digit at the end, when your other pages hide it inside?
Because putting it inside would break the only thing this tool sells. A cracking rule does try trailing digits first, which is why the memorable password generator scatters them — but nobody can read "bak7lomi" down a phone line. The digit goes on the end and is not counted toward the entropy figure.
Could it produce something embarrassing?
Not from a list of about sixty substrings it refuses to emit. It is a genuine risk rather than a theoretical one: the prototype for this page produced an obscenity within its first dozen samples. Roughly one draft in twenty-three is discarded and redrawn, which costs 0.066 bits.
Does discarding drafts make the result less random?
It shrinks the space slightly, and rejection keeps everything that survives equally likely. That is why drafts are thrown away rather than patched: changing a letter would bias the output in a way that is hard to see and harder to measure. The cost is measured over twenty thousand draws, not guessed.
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The syllable set
19 single consonants and 19 clusters can start a syllable; 5 short vowels can follow either, and 5 vowel pairs can follow a single consonant only. That is 285 syllables. A final consonant ending is drawn from 23 options, one of which is nothing at all. No word list is involved at any point.
How the draw works
possibilities = 285syllables × 23
Every syllable comes from crypto.getRandomValues() through rejection sampling, and the set is enumerated before any drawing happens, so each syllable is equally likely.Math.random() is never used anywhere in this pronounceable password generator.
Why the count is exact
A syllable has a consonant part and a vowel part and nothing else, so the finished password alternates consonant and vowel runs and its boundaries are forced.
The unit tests generate passwords, split them back into syllables, and assert the round trip. That is what shows the mapping is one-to-one and the possibility count is not double-counting anything.
The blocked list
About sixty substrings the generator will not emit, applied by rejection. The measured rejection rate at five syllables is 4.3%, costing 0.066 bits. The list is in the source and is checked by tests for duplicates and for entries too short to be safe.
What is not counted
The optional digit and symbol. Their position is fixed and their presence is announced by the form that demanded them, so including them would flatter the figure. Nothing generated here is transmitted, stored, placed in the URL or attached to an analytics event.