Does my password leave my browser?

No. Generation, entropy math and breach check all run client-side. The breach check uses k-anonymity — only first 5 chars of the SHA-1 are sent to the breach API.

Which RNG do you use?

crypto.getRandomValues() — the same CSPRNG your browser uses for TLS keys. Never Math.random().

How do you calculate entropy?

log2(charset_size^length) for random passwords; log2(wordlist_size^words) for passphrases. Real entropy, not a marketing number.

Do I get a free trial?

No — this is a paid tool with plans from $5 a month. Starter is $5/mo and Pro is $15/mo; you can cancel any time.

Account page or email. Cancellation stops the next renewal.

PasswordForge · password strength

What is a sensible minimum password length?

Strength is not a property of how a password looks. It is the size of the set it was drawn from, expressed in bits, and it only means anything when the password was chosen at random.

These numbers describe a password generated at random. A password a person invented — a name, a date, a word with letters swapped for digits — is worth a fraction of the same length, because an attacker guesses the pattern, not the alphabet. Entropy measures the dice, not the string.

Entropy and keyspace

Alphabet	Entropy	Possible passwords	Verdict
8 characters, letters and digits	47.6 bits	218,340,105,584,896	fair
12 characters, letters and digits	71.5 bits	3.23×10^21	strong
16 characters, with symbols	103.1 bits	1.08×10^31	great
4-word passphrase	51.7 bits	3.66×10^15	fair
6-word passphrase	77.5 bits	2.21×10^23	strong

Time to exhaust half the keyspace

Each column states the guess rate it assumes. A crack time quoted without a rate is meaningless — the same password is minutes or millennia depending on whether the attacker is typing into a login form or running eight GPUs against a stolen hash.

Attack	47.6b	71.5b	103.1b	51.7b	77.5b
Online, rate-limited (10 guesses/sec)	345,939 years	5.1×10^12 years	1.7×10^22 years	5.8×10^6 years	3.5×10^14 years
Online, no throttling (1 000/sec)	3,459 years	5.1×10^10 years	1.7×10^20 years	57,928 years	3.5×10^12 years
Offline, slow hash — bcrypt cost 12 (20 000/sec)	173 years	2.6×10^9 years	8.5×10^18 years	2,896 years	1.8×10^11 years
Offline, fast hash — salted SHA-256 on 8 GPUs (100 billion/sec)	18 minutes	511 years	1.7×10^12 years	5.1 hours	35,027 years
Offline, well-funded (100 trillion/sec)	1.1 seconds	187 days	1.7×10^9 years	18 seconds	35 years

Generate one at this strength

The generator runs in your browser using the operating system's cryptographic random source — nothing is sent anywhere. Pick a length or a word count, see the entropy update as you go, and export a batch when you need many at once.

Open PasswordForge

What is a sensible minimum password length?

Entropy and keyspace

Time to exhaust half the keyspace

Other strength questions