Password Generator
Generate up to 10 random passwords of 4 to 128 characters from the character sets you check: uppercase, lowercase, numbers and symbols. The passwords are generated in your browser, and the page shows the bits of entropy each one has.
How to use the Password Generator
- Enter your numbers in the Password Generator above.
- Press the Generate Passwords button to see the result.
- To try other numbers, change any value and press the button again.
Password entropy
Bits of entropy = length × log₂(character set size)
The generator draws every character on its own from your browser's cryptographic random source, crypto.getRandomValues, and each character in the set is equally likely. With all four boxes checked the set has 88 characters: 26 uppercase, 26 lowercase, 10 digits and 26 symbols. Each character then adds log₂(88) ≈ 6.46 bits, so 12 characters give about 77.5 bits and 16 give about 103.4. Entropy counts how many passwords the generator could have produced. A shorter length or fewer character sets lowers it.
Worked example
With the default settings, 16 characters and all four sets, the generator picks each character from 88 possibilities. That is 88¹⁶ possible passwords, about 103.4 bits of entropy. Uncheck symbols and the set drops to 62 characters, which gives 16 × log₂(62) ≈ 95.3 bits.
Frequently asked questions
Is the password created on my device?
Yes. The page builds each password in your browser with crypto.getRandomValues and does not send it to a server. Reload the page and the passwords are gone, so copy the one you want first.
Does every password contain a digit and a symbol?
Not always. Each character is drawn from the whole set, so a password can miss one of the checked sets by chance. With all four sets and 16 characters, about 14.5% of passwords have no digit and about 0.4% have no symbol. If a site demands one of each, generate again.
What length should I use?
Each extra character multiplies the number of possible passwords by the size of the character set, which is 88 with all four sets checked. 8 characters give about 52 bits of entropy, 12 give about 78 and the default 16 give about 103. Some sites cap the length or reject certain symbols, so check their rules before you generate.
Should I reuse passwords?
Never. A breach at one site exposes the password at every site using it. A password manager can store a different password for every account.