Password Strength Checker — Security Analyzer

Free, private password strength checker. Analyze entropy, crack time, and security score. Detects common passwords, repeated/sequential characters — 100% client-side, password never leaves your device.

🔒 100% Private
Completely Free
🌐 Runs in Browser
📦 Export Ready

Password Strength Checker — Security Analyzer

Tool Workspace

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  1. Enter your password in the field (or generate one).
  2. See the strength meter — color-coded from red (very weak) to green (very strong).
  3. Review checks — length, uppercase, lowercase, numbers, symbols, entropy.
  4. Check warnings — common password detection, repeated/sequential characters.
  5. See crack time — estimated time to brute-force your password.

What Is the Password Strength Checker?

The Password Strength Checker is a free, privacy-first tool for analyzing the security of your passwords. It evaluates multiple strength factors including length, character variety, entropy, and pattern detection — all without sending your password anywhere.

Key Features

  • Visual Strength Meter — Color-coded bar from red (very weak) to green (very strong).
  • Entropy Calculation — Measures password randomness in bits.
  • Crack Time Estimation — How long it would take to brute-force at 10 billion guesses/second.
  • Common Password Detection — Flags the 25 most commonly used passwords.
  • Pattern Detection — Warns about repeated characters and sequential patterns.
  • Strong Password Generator — Generate 20-character passwords with one click.
  • Security Checklist — Visual checks for length, uppercase, lowercase, numbers, symbols.
  • 5-Language Support — EN, AR, ES, PT, ZH.

Privacy & Security

This tool is designed with privacy as its core principle. Your password is NEVER sent to any server. All analysis happens entirely in your browser using JavaScript. No data is transmitted, stored, or logged.

Comparison

FeatureServerless Toolshaveibeenpwnedpassword.kaspersky
No Server Upload100% localHash sentPassword sent
EntropyYesNoNo
Crack TimeYesNoYes
GeneratorYesNoNo

Frequently Asked Questions

Does my password leave my device?

Absolutely not. This tool runs 100% in your browser using JavaScript. Your password is never sent to any server, stored anywhere, or logged. It stays entirely on your device.

How is strength calculated?

The tool evaluates multiple factors: length, character types (uppercase, lowercase, numbers, symbols), entropy (randomness), and checks for common passwords, repeated characters, and sequential patterns.

What is entropy?

Entropy measures the randomness of a password in bits. Higher entropy means more possible combinations and greater security. A password with 60+ bits of entropy is considered strong.

How accurate is the crack time?

The crack time assumes 10 billion guesses per second (modern GPU capability). Real crack times vary based on the attacker's resources and method.

Can I generate a strong password?

Yes. Click the 🎲 dice button to generate a 20-character password with uppercase, lowercase, numbers, and symbols. It's automatically copied to your clipboard.

What makes a password common?

The tool checks against a list of the 25 most commonly used passwords worldwide (e.g., 'password', '123456', 'qwerty'). If your password matches, it's flagged as very weak.