Strong password generator
Choose the length and character types, and the tool builds a password with at least one character of each chosen type. The password is never sent anywhere.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter length, upper case a-z, lower case a-z, digits 0-9, symbols like ! @ # $ and leave out look-alikes i l 1 o 0 o.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Each character is chosen evenly from the selected pool with crypto.getRandomValues, and a password missing a chosen type is rejected. Strength in bits = log2 of the number of possible passwords, counted exactly by inclusion-exclusion: sum of (-1)^|S| × (pool - sizes of types in S)^length.
Example
Inputs: Length = 16 chars, Upper case A-Z = yes, Lower case a-z = yes, Digits 0-9 = yes, Symbols like ! @ # $ = yes. Result: Password: tGR[#shmj}uE%7O.; Length: 16; Character pool: 94.
Limits and caveats
- The rating cut-offs (28, 36, 60 and 128 bits) are a common rule of thumb, not an official standard.
- Some sites reject certain symbols, so turn symbols off if a password is refused.
Questions about this tool
Is the password private?
It is generated in your browser with crypto.getRandomValues and is never sent or stored anywhere.
What length should I use?
Sixteen characters with all types gives about 104 bits, enough for most accounts, ideally kept in a password manager.
What does strength in bits mean?
Each extra bit doubles the guesses needed, so a 60-bit password takes up to about 2^60 guesses to find.