Free Password and Passphrase Generator

For important accounts like banking and email, use at least 16 characters. A 20+ character password with mixed character types is practically uncrackable even with modern GPU clusters. This generator supports up to 64 characters.

We calculate entropy (randomness in bits) from how your password was generated: its length and character pool, or for a passphrase its number of words, then estimate how long a brute-force attack would take across 4 realistic scenarios: online throttled attacks (100 guesses/sec), online fast attacks (1,000/sec), offline attacks against bcrypt/Argon2 hashes (50,000/sec), and offline attacks against weak MD5/SHA1 hashes using a modern 8x RTX 4090 GPU cluster (100 billion/sec).

A passphrase like "wolf-thunder-castle-42" is both secure and memorable. Each word picked at random from the 7,776 word list this generator uses (the EFF long list) adds about 12.9 bits, so five or more words resist brute-force attacks. The key is that the words must be randomly selected, not chosen by a human. This generator uses cryptographically secure randomness (Web Crypto API).

Yes. All passwords are generated entirely in your browser using the Web Crypto API (crypto.getRandomValues). No passwords are ever sent to a server, stored in a database, or logged anywhere. The tool works fully offline after the page loads.

A strong password has high entropy, meaning it's long, uses diverse character types (uppercase, lowercase, numbers, symbols), and is randomly generated rather than human-chosen. Avoid dictionary words, personal info, and common patterns. The strength meter here reports the entropy of the settings you chose, which is exact for a generated password and does not apply to one a person made up.

Short or simple passwords, yes. A 6-character lowercase password has only ~300 million combinations, which a GPU can exhaust in under a second. But a 16-character password with mixed types has over 10^30 combinations, which would take billions of years. Length and character variety matter enormously.

Entropy measures password randomness in bits. For a random password it's calculated as length × log2(pool size), where pool size is the number of possible characters. For a passphrase it's the number of words × log2(word list size), because the words are random, not the letters. Higher entropy = harder to crack. Under 36 bits is weak, 60 to 80 is strong, and 100+ bits is practically unbreakable.

Math.random() is not a cryptographic generator: its internal state can be recovered from a handful of outputs, after which every later value is predictable. This tool uses crypto.getRandomValues, the browser’s cryptographically secure source, and rejects draws from the uneven tail of the 32-bit range so every character and word is exactly equally likely.

Never in plain text and never as a fast hash like MD5 or SHA-256. Store a slow, salted password hash: Argon2id first, then scrypt or bcrypt, with PBKDF2 where FIPS compliance requires it. The free Password Hasher on this site generates and verifies all four, with the OWASP parameters.