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

How strong is a 20-character password?

A random 20-character password carries between 94 and 128.9 bits of entropy, depending on which characters it may contain. The table below gives the exact figure for each alphabet, and what each attack speed would need to exhaust it.

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
Lowercase letters (a-z)	94 bits	1.99×10^28	great
Letters, both cases (A-Z a-z)	114 bits	2.09×10^34	great
Letters and digits (A-Z a-z 0-9)	119.1 bits	7.04×10^35	great
Letters, digits and symbols	128.9 bits	6.17×10^38	extreme

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	94b	114b	119.1b	128.9b
Online, rate-limited (10 guesses/sec)	3.2×10^19 years	3.3×10^25 years	1.1×10^27 years	9.8×10^29 years
Online, no throttling (1 000/sec)	3.2×10^17 years	3.3×10^23 years	1.1×10^25 years	9.8×10^27 years
Offline, slow hash — bcrypt cost 12 (20 000/sec)	1.6×10^16 years	1.7×10^22 years	5.6×10^23 years	4.9×10^26 years
Offline, fast hash — salted SHA-256 on 8 GPUs (100 billion/sec)	3.2×10^9 years	3.3×10^15 years	1.1×10^17 years	9.8×10^19 years
Offline, well-funded (100 trillion/sec)	3.2×10^6 years	3.3×10^12 years	1.1×10^14 years	9.8×10^16 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

How strong is a 20-character password?

Entropy and keyspace

Time to exhaust half the keyspace

Other strength questions