Password Generator (Strong, Random, Private)
Choose the length and character types; a new password appears instantly.
Password Generator (Strong, Random, Private) by TheCalcTools
How the Password Generator (Strong, Random, Private) works
Each character is picked independently and uniformly from the character types you choose, using your browser’s cryptographic random generator. The password always contains at least one character of every type you tick.
Strength is measured as entropy: length × log₂(number of possible characters). Each extra bit doubles the guesses an attacker needs. 80 bits or more is very strong for online accounts; use a password manager so you do not have to remember them.
The password is created on your device and never sent anywhere or stored by this page.
The formula
Worked example
With length 20 and all four character types (87 possible characters), each password has 20 × log₂ 87 = 128.9 bits of entropy, rated Excellent.
Frequently asked questions
How long should a password be?
At least 16 characters for important accounts if you use a password manager. A 20-character password from all four types has about 129 bits of entropy.
Is a passphrase better?
Several random words can be as strong and easier to type. What matters is that the choice is random and long enough.
Sources and further reading
Related calculators
More in Calculators & Generators · All calculators
This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.