🛡️Cybersecurity
Password Strength Checker
How long would it take an attacker to crack your password? This password strength checker uses cryptographic entropy — a measure of unpredictability — to calculate the estimated time to crack your password under a brute-force attack. Your password is analysed entirely in your browser; it is never transmitted to any server. The tool evaluates character set diversity, length, and common patterns to give you a realistic strength rating and actionable improvement suggestions.
Your password never leaves your browser. All analysis runs locally in JavaScript. Nothing is transmitted or stored.
Crack time assumes 1 billion guesses/second (modern GPU brute-force). Does not check against known leaked password databases.
Frequently Asked Questions
Is it safe to enter my real password here?
This tool processes your password entirely client-side in your browser using JavaScript. No data is transmitted to any server, stored in any database, or logged. However, as a general security rule, avoid entering critical passwords into any online tool.
What makes a password strong?
Password strength is primarily determined by length and character diversity. A 16-character password using uppercase, lowercase, numbers, and symbols has significantly more entropy than an 8-character password using only letters. Randomness matters too — avoid dictionary words, names, and predictable substitutions.
What is password entropy?
Entropy is a measure of unpredictability, expressed in bits. Each bit doubles the number of possible combinations an attacker must try. A password with 60 bits of entropy has over a quintillion possible combinations — highly resistant to brute-force attack.
How do attackers crack passwords?
Common methods include brute-force (trying every combination), dictionary attacks (using common words and variations), credential stuffing (using leaked passwords from other breaches), and rainbow table attacks (pre-computed hash lookups). Length and randomness defeat most of these.
Should I use a password manager?
Yes. Password managers generate and store long, random, unique passwords for every account. This eliminates both weak passwords and password reuse — two of the most common causes of account takeovers. Leading options include Bitwarden (open source), 1Password, and Dashlane.