A weak or reused password is the leading cause of online account compromise. Generating a strong, unique password for each service is the foundation of digital security. An online generator produces random passwords according to customizable criteria in one click.
A strong password combines length and character diversity. Length is the most important factor: each additional character exponentially multiplies the number of possible combinations. A 12-character password with letters + digits + symbols has 4.7 × 10²³ combinations. Password managers (Bitwarden, 1Password, Dashlane) allow using strong passwords without memorizing them.
📐 Formula
Entropy (bits) = log₂(N^L) = L × log₂(N) where N = alphabet size, L = length
📊 Reference table
| Length | Alphabet | Combinations | Brute force time (2025) |
|---|---|---|---|
| 8 digits | 10 | 10⁸ | < 1 second |
| 8 lowercase | 26 | 2.1 × 10¹¹ | A few minutes |
| 8 mixed (az+AZ+09) | 62 | 2.2 × 10¹⁴ | ~1 hour (GPU) |
| 12 mixed + symbols | 94 | 4.7 × 10²³ | Billions of years |
| 16 mixed + symbols | 94 | 3.7 × 10³¹ | Practically impossible |
💡 Practical examples
Example 1: password for a bank account
Length: minimum 16 characters. Include: uppercase, lowercase, digits, symbols (!@#$%). Example: gT7#kP2mN!qR8dXv. Never reuse, store in a password manager.
Example 2: memorable password (passphrase)
4 random words separated by hyphens: Chocolate-Rocket-Cloud47-Desk gives ~48 bits of entropy and remains memorable. Technique recommended by NIST.
Example 3: entropy of a common password
"password": entropy ≈ 38 bits (in dictionaries, cracked in < 1 second). "P@ssw0rd!": although complex-looking, present in hybrid dictionaries, cracked in seconds.