Generate strong, random passwords with customizable length, character types, and strength indicator.
What is Password Generator?
This password generator produces cryptographically strong random passwords using the <code>window.crypto.getRandomValues()</code> API — the same source of randomness browsers use for cryptographic keys. That means the output is genuinely unpredictable, not based on <code>Math.random()</code> which is fine for games but unsafe for security. Choose a length between 4 and 64 characters, toggle uppercase, lowercase, digits, and symbols, and the generator produces a fresh password on each click. Nothing is ever transmitted or logged; passwords exist only in your browser tab and disappear when you close it.
How to Use
Adjust password length with the slider
Toggle character types
Click Generate New for a fresh password
Copy to clipboard
What actually makes a password strong
Password strength is measured in entropy — the number of guesses an attacker would need to try. Entropy is calculated from two things: the size of the character pool, and the length of the password. Length matters far more than complexity.
Length
Character set
Entropy
Time to crack (offline)
8 chars
lowercase only (26)
~38 bits
seconds
8 chars
mixed + digits + symbols (94)
~52 bits
hours
12 chars
mixed + digits + symbols (94)
~78 bits
centuries
16 chars
mixed + digits + symbols (94)
~105 bits
trillions of years
20 chars
lowercase only (26)
~94 bits
billions of years
Note the last row: a 20-character all-lowercase password is stronger than a 12-character mixed-case one with symbols. This is why security researchers (and the current NIST guidelines) now recommend long passphrases — strings of 4–6 random words — over shorter "complex" passwords. They're easier to remember and harder to crack.
The two rules that actually matter: length and uniqueness
Most password-strength advice from the 2000s has been debunked. Here's what current security guidance (NIST 800-63B, the current authoritative standard) says:
Length beats complexity. Aim for at least 12 characters for general accounts, 16+ for critical ones (email, banking, password manager).
Never reuse passwords. When one site gets breached, attackers try the leaked passwords on every other site. Password reuse is how 90 % of account takeovers happen. Use a password manager.
Forced periodic changes are counterproductive. NIST now explicitly recommends against forcing password changes every 90 days, because people just make trivial modifications (Password1 → Password2). Only change a password if you suspect it's been compromised.
Skip security questions when possible. "Mother's maiden name" is a public record in most countries. If you must answer one, treat the answer as another password — make it random and store it in your password manager.
Where does a generated password go next?
A strong random password you can't remember is still useless if you lose it. Three common approaches, from best to worst:
Password manager (recommended) — 1Password, Bitwarden, Dashlane, iCloud Keychain, or the built-in manager in Chrome, Firefox, or Safari. The manager generates and stores unique 20+ character passwords per site, and auto-fills them. You remember one strong master passphrase, the manager handles the rest. This is what every security professional actually does.
Written in a notebook — surprisingly effective for a small number of critical passwords, if the notebook never leaves your house. The threat model for most people is online credential theft, not physical burglary.
Reused across sites, slightly modified (e.g., adding the site name to the end) — unsafe. Breach compilations contain billions of leaked passwords; attackers specifically look for patterns like this.
If you're using this generator for a master password you'll need to memorise, consider the diceware passphrase approach instead: pick 5–6 random common words, separated by spaces or hyphens. "correct horse battery staple" has more entropy than "Tr0ub4dor&3" and is far easier to remember.
Frequently Asked Questions
Are these passwords secure?
Yes. They are generated using the Web Crypto API with cryptographically secure random values, entirely in your browser.
Is my password stored?
No. Passwords are generated locally and never sent to any server.
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