Six random words are within 1.1 bits of 12 random characters. You can say them out loud.
Roll the words below with your browser's secure random generator, or with five physical dice: every word shows its dice code. Nothing is sent anywhere and nothing is stored.
How strong is it?
bits of entropy
random characters (94 symbols) with the same strength
random lowercase letters with the same strength
064 bits128 bits
How long would a guesser need?
Average time to find it is half the search space. The guess rate is your assumption, since it depends on how the secret is stored; pick the scenario you worry about.
Guess first: how many words match 12 random characters?
A password of 12 characters, each picked at random from the 94 printable ASCII symbols, is hard to type and impossible to memorise. How many random words from this 7,776 word list give the same strength or more?
Words versus bits
Words
Bits
Search space
Random chars (94) equal
How it works
The list has 7,776 words, which is 6 to the power 5: five dice rolls pick one word, so each word adds log2(7776) = 12.92 bits. The browser draws each word with crypto.getRandomValues and rejection sampling, so every word is equally likely. The strength only holds when the words are chosen at random: a phrase you invent yourself is far weaker. Entropy assumes the attacker knows the list and the method.
94 symbols: the printable ASCII characters from "!" to "~", excluding space (code points 33 to 126). All bit counts and times on this page are computed by the page from these two numbers and your guess-rate assumption.