Password Generator
How strong is a 16-character password, really? Generate one here — built locally in your browser with the Web Crypto API and never transmitted — and see exactly how many bits of entropy it carries and how long it would survive a brute-force attack.
Your password
Entropy
104.9
bits (94-char pool)
Strength
Very strong
<50 weak · >80 very strong
Avg. crack time
59 trillion years
at 10¹⁰ guesses/sec
Passwords are generated locally with the Web Crypto API (crypto.getRandomValues) using rejection sampling, so every character is drawn uniformly — and nothing is ever transmitted or stored. Each selected set is guaranteed at least one character.
Why Length Beats Complexity
Password strength is measured in entropy bits: length × log₂(pool size). Each added character multiplies the search space by the whole pool, while each added charactertype only nudges the pool size up — so 16 characters drawn from the full 94-character printable set carry about 105 bits (16 × 6.55), which at ten billion guesses per second would take an average of roughly 59 trillion years to crack. An 8-character lowercase password carries just 37.6 bits and falls in about 10 seconds at the same rate.
Entropy vs. average crack time (10¹⁰ guesses/sec)
8 chars, lowercase only 37.6 bits ~10 seconds 12 chars, all four sets 78.7 bits ~750,000 years 16 chars, all four sets 104.9 bits ~59 trillion years Entropy = length × log2(pool size) Pools: lowercase 26 · +uppercase 52 · +digits 62 · +symbols 94
Frequently Asked Questions
How long should a password be in 2026?
16 random characters is the practical sweet spot: drawn from the full 94-character set it carries ~105 bits of entropy, which would take an average of ~59 trillion years to brute-force at 10 billion guesses per second. NIST guidance now favors length over forced complexity rules — 12 truly random characters (~79 bits) is a reasonable floor, 8 is not.
Is it safe to generate a password in my browser?
Here, yes — passwords are produced locally by the Web Crypto API (crypto.getRandomValues), which pulls from your operating system's entropy pool, and nothing is sent over the network or stored. The risk with online generators is server-side generation or logging; this page does neither, and you can verify by loading it and disconnecting before generating.
What is password entropy and how is it calculated?
Entropy in bits = length × log₂(pool size), measuring how many guesses an attacker needs (2^bits on average ÷ 2). An 8-character lowercase password is 8 × log₂(26) ≈ 37.6 bits — crackable in seconds — while 16 characters from all four sets is 16 × log₂(94) ≈ 105 bits. Each extra character multiplies the search space by the full pool size, which is why length beats complexity.
Should I exclude ambiguous characters like O, 0, and l?
Only if you'll ever read or type the password manually — O/0 and I/l/1 are easily confused in many fonts. The security cost is tiny: removing those 5 characters shrinks the pool from 94 to 89, costing about 1.3 bits at 16 characters (104.9 → 103.6 bits). If a password manager autofills it, leave them in.