How it is calculated
Characters come from the browser’s cryptographic generator when one is available. The entropy estimate is the length times the logarithm of the alphabet size. That is an upper bound for a random string, not the strength of a password built from dictionary words.
Bits ≈ length × log2(size of the alphabet)
Where the numbers come from
- Length — unit in the field: characters
- Lowercase letters
- Uppercase letters
- Digits
- Symbols
- Without similar characters 0, O, 1, l
Example
12 characters drawn from letters, digits, and symbols give an entropy estimate of about 70+ bits. The exact figure depends on the alphabet size.
Questions
Is the password stored somewhere?
No. The page does not send it to a server. Copy it into a password manager.
Why leave out similar letters?
So that 0 and O, and 1 and l, are not confused when you type. A paste from the clipboard does not need it.
Is a phrase of words safer?
A long random passphrase is often easier than a short scramble. This generator makes exactly that scramble of characters.