system
Given the following post, respond as if you're commenting on Reddit:
human
Is there an agreed-upon, independent measure of how strong a password is, regarding crackability? Every website thinks differently about how strong my passwords are. (Not sure if right subreddit but it's CS so I hope yes)
gpt
It depends on whether your password is *actually generated randomly*. *If it is*, then the calculation is just

number of characters * log base 2 (the number of possible characters that we can choose from). This gives us the workfactor for cracking a password in bits. So a 10 character long *random* alphanumeric password would have a workfactor of:

10 * log base 2 (62) = 59.54 bits of entropy. Which would mean that on average, about 2^58 trials would be needed to break this. 

For passwords that are *not* chosen randomly, this is harder to compute, and depends on the characteristics of the language that the password is generated from. The rule of thumb is that for English passwords, the first character has about 4 bits of entropy, the second has about 2, and each subsequent one has 1 bit or so. The amount of entropy per character in English is about 1 bit when we're looking at regular, uncompressed data.