Your answer starts here
Enter your values and select Calculate to see the result and its breakdown.
How it works
Unique characters differ from unique passwords
The no-repeat option controls characters inside one password; it does not make reusing that password across accounts safe. Generate a separate password for each account. Avoid interpreting a character restriction as a substitute for account-by-account uniqueness.
Choosing password length and allowed characters
Set the length and character options to fit the destination's requirements before generating a password. Restricting the character set changes the range of possible outputs, so avoid unnecessary restrictions when the service permits them. A generated password still needs to be stored securely and used for its intended account. The tool does not assess the security of the website where it will be entered.
Generate passwords: formula and assumptions
Select characters with cryptographic random bytes and unbiased rejection sampling, then securely shuffle.
Every password includes lowercase, uppercase, and digits, plus a symbol when enabled. Save passwords in a reputable password manager.
Custom character options: formula and assumptions
Uniform random candidates are accepted only if all selected character classes appear.
Cryptographic rejection sampling avoids modulo bias and preserves uniformity among allowed passwords. Unique-character mode securely shuffles the pool. Everything runs locally.
Formula references
References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.
Common questions
Will every selected character class appear in a generated password?
The generator requires each selected class to appear, subject to the supported length and character-pool constraints.
Does unique-character mode work at any password length?
No. A password cannot contain more unique characters than the available selected pool. Repetition limits constrain the permitted length.
Prepared by Finflo. See our methodology and editorial policy.