Password Strength Checker – Test Password Entropy & Security

A password strength checker evaluates the computational resistance of a password against brute-force and dictionary attacks by calculating its bit entropy and simulated offline cracking duration. All analysis takes place in client-side JavaScript memory.

The tool determines the effective character search space, penalizes common patterns and sequential repetitions, and computes estimated cracking times across realistic attack profiles from consumer hardware to state-sponsored parallel computing arrays.

A password keyspace represents the total quantity of distinct permutations possible under a given length and character alphabet (Keyspace = N^L). While online attacks are throttle-limited by web application rate limits and CAPTCHAs, offline attacks occur after a database breach where an attacker attempts billions of hashes per second against extracted password hashes.

Modern GPU clusters running optimized hashcat kernels can calculate billions of NTLM or fast MD5 hashes every second. Consequently, passwords intended for sensitive accounts must maintain sufficient entropy to make offline keyspace exhaustion computationally infeasible even if salted hashes are compromised.