Security Tool

Password Strength Checker

Analyze your password's entropy, detect weak patterns, estimate crack time, and generate fortress-grade passwords — entirely inside your browser.

100% Client-Side Zero Data Transmitted Unlimited Free Checks Real-Time Analysis

Password Analyzer

Very Weak Weak Fair Strong Very Strong
Enter a password to begin analysis
0
Characters
0
Entropy (bits)
0
Charset Size
Estimated crack time: —
12+ characters
Uppercase (A-Z)
Lowercase (a-z)
Numbers (0-9)
Special chars (!@#$)
No repeated chars
No sequential patterns
Not a common password
How to improve this password

    Password Generator

    8 64
    Click generate to create a password
    Very Weak Weak / Fair Strong Very Strong

    How to Use This Tool

    From a weak password to an uncrackable one in four steps.

    1

    Enter Your Password

    Type or paste any password into the analyzer input. Use the eye icon to toggle visibility. Analysis starts instantly with every keystroke — no submit button needed.

    2

    Read the Strength Report

    The strength meter, entropy score, character count, and estimated crack time all update in real time. The criteria checklist shows exactly which security rules you are passing or failing.

    3

    Act on the Suggestions

    If the password has weaknesses, a tailored suggestion list appears below the checklist. Each tip tells you exactly what to add or remove to dramatically increase security.

    4

    Generate a Better One

    Use the Password Generator — set length (up to 64 chars), pick character types, optionally exclude ambiguous characters, and click Generate. The new password flows straight into the analyzer.

      Security Best Practices

    • Use a different password for every account — reuse is the single biggest security risk.
    • Store generated passwords in a password manager (Bitwarden, 1Password, KeePass) — not a notes app.
    • Aim for 60+ bits of entropy for standard accounts, 80+ bits for banking and email.
    • Enable two-factor authentication (2FA) even on strong passwords — it adds a second barrier.
    • Avoid personal details — names, birthdays, and pet names are guessed first in targeted attacks.
    • Longer beats complex: a 5-word passphrase is stronger than a short mixed-character password.

    What This Checker Analyses

    Far beyond a simple length check — every password is scored across seven dimensions.

    Entropy Scoring

    Shannon entropy is calculated from your password length and character set size, giving a precise measure of unpredictability in bits — not just a color grade.

    Crack Time Estimate

    Based on entropy and a conservative 10 billion guesses per second benchmark — see whether your password lasts milliseconds or millions of years under attack.

    Pattern Detection

    Detects keyboard walks (qwerty, 12345), repeated characters (aaaa), sequential patterns (abcd), and common dictionary passwords that look strong but are not.

    8-Point Criteria Check

    Every password is checked against eight rules: length, uppercase, lowercase, numbers, symbols, no repetition, no sequences, and no common patterns.

    Actionable Suggestions

    Instead of just labeling your password as weak, the tool tells you exactly why and gives specific, prioritized steps to fix it.

    Advanced Generator

    Generate passwords up to 64 characters with full control over character types and exclusion of visually ambiguous characters like O, 0, l, and 1.

    Frequently Asked Questions

    Everything you need to know about password security and how this tool works.

    Yes — on this tool, completely. The entire analysis runs inside your browser using JavaScript. Your password characters are never transmitted to any server, never logged, and never stored. To verify it, turn off your internet connection and try the tool — it works perfectly offline.
    Entropy is a measure of how many guesses an attacker would need to crack your password, expressed as a power of 2 in bits.

    Below 40 bits — Weak. Crackable in seconds to hours.
    40 to 59 bits — Fair. Better, but vulnerable to sustained attacks.
    60 to 79 bits — Strong. Suitable for most everyday accounts.
    80+ bits — Very Strong. Recommended for email, banking, and work systems.
    Length helps, but predictability defeats it. "passwordpassword" is derived from one of the most common passwords in the world. Attackers use dictionary attacks — they test millions of word combinations and repetitions before resorting to pure brute force. Our checker detects common patterns and repeated structures and scores them accordingly, regardless of raw length.
    A keyboard walk is a sequence of characters that follow a physical path on a keyboard — for example "qwerty", "1qaz2wsx", or "zxcvbn". They feel random to a human eye but are extremely common and among the first patterns tested in dictionary and credential-stuffing attacks. This tool detects keyboard-walk patterns and warns you when your password contains them.
    Crack time is estimated by calculating the total number of possible passwords (2 to the power of entropy bits) and dividing by a conservative benchmark of 10 billion guesses per second — a realistic figure for a modern GPU-based offline attack. The result is shown in human-readable format from seconds to billions of years. Online attacks are much slower due to rate limiting.
    For most accounts, 16 characters is the minimum we recommend. For critical accounts such as email, banking, and cloud storage, aim for 20 or more characters. Using all four character types at 16 characters gives roughly 105 bits of entropy — which would take longer than the age of the universe to brute-force at 10 billion guesses per second.
    Passphrases (for example "purple-blanket-mountain-forge") can be both secure and memorable when done correctly. A 5-word passphrase from a large wordlist gives about 64 bits of entropy. However, they are generally weaker than truly random 16+ character passwords with mixed character types. For critical accounts, use a random password stored in a password manager.
    Characters like uppercase O and zero (0), lowercase l and number 1 look nearly identical in many fonts. If you ever need to read a generated password from a screen and type it elsewhere — for example into a TV, gaming console, or legacy system — ambiguous characters cause transcription errors. The exclude ambiguous option removes them without meaningfully reducing entropy at 16 or more character lengths.
    Copied to clipboard!