Estimate the brute-force search space implied by a password's length and detected character classes.
⚠️ Estimator only, not a real security audit. Entropy assumes uniform random selection from character classes (not how humans actually choose passwords). Crack time assumes 1e10 guesses/sec and half-keyspace search. Real password risk depends on predictability, dictionary attacks, breached-password lists, and actual attacker resources. A password with high entropy here can still be weak if predictable.
Last updated: March 2026 | By Patchworkr Team
Your password is evaluated locally and never transmitted or stored.
Password entropy is a measure of the randomness and strength of a password, expressed in bits. It quantifies how many possible passwords could exist given the character set and length. Higher entropy means more possible passwords and longer attack times for brute-force cracking.
Entropy is calculated using the formula: Entropy = log₂(pool_size^password_length), where pool_size is the number of characters available (lowercase, uppercase, digits, symbols) and password_length is the number of characters in the password. A password with 80 bits of entropy is considered strong protection against modern attacks.
However, entropy alone doesn't determine security. Dictionary attacks, pattern recognition, and leaked password databases can crack weak passwords faster than entropy suggests. True entropy requires randomness; predictable passwords (like "Password123") have much less effective strength despite normal entropy calculations.
The calculator counts which character types are present:
This equals the logarithm (base 2) of all possible password combinations. Each additional bit of entropy doubles the attack time.
Calculate entropy for "MyP@ssw0rd!":
~94 quadrillion combinations, years to crack
High entropy helps, but it's not the only factor. Leaked passwords, social engineering, malware, and password reuse are common attacks. Use unique, random passwords everywhere.
80 bits protects against brute-force attacks using current technology. However, quantum computers could change this. NIST currently recommends 112+ bits of entropy.
Each character adds exponential strength. A 12-char password with lowercase is stronger than 8-char with all character types. Length is the primary entropy driver.
Modern security science says no, unless compromised. Focus on strong unique passwords and multi-factor authentication instead of periodic changes.
Password managers are excellent—they enable long, random, unique passwords for every account. Use a strong master password (60+ bits entropy minimum).
GPUs can attempt billions of guesses per second. With 10B guesses/sec: 40-bit password cracks in hours, 60-bit in days, 80-bit in centuries.
Yes! Passphrase of 4 common words (11.3 bits each ≈ 45 bits total) is better than short complex passwords. But random is better than memorable.
Adding special characters increases pool size modestly. As least one special char adds only 5-6 bits. Length matters far more than forced complexity.
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