Password strength checker | Enhance Your Password Security

Use our Password Strength Checker to evaluate your passwords. It measures strength, identifies vulnerabilities, and estimates cracking time. Get tips to improve security and protect your online accounts.


Checked entirely in your browser Your password is never sent anywhere. All strength analysis happens on your device, in JavaScript, and nothing is stored or transmitted.
Your password is never stored or sent anywhere

Key Features

Real-time evaluation of password strength
Detailed breakdown of security criteria
Personalized improvement suggestions
Estimated hack time for brute-force attacks
Password entropy visualization
Character distribution analysis
Pattern detection and analysis
Common password pattern detection
Mobile-friendly interface
No data storage or transmission

Use Cases

Check if your current passwords are secure
Learn about good digital security practices
Complement the Local Password Generator in Mezuto
Create strong passwords for new accounts
Verify password security before important changes

How to Use

1 Enter your password in the field above
2 View the strength evaluation and suggestions
3 Follow the recommendations to improve your password
4 Review the security criteria breakdown
5 Implement the suggested improvements

Tips for a Stronger Password

  • Use a passphrase of four or more random words instead of a single word.
  • Make it long: every extra character makes cracking exponentially harder.
  • Use a unique password for every account so one breach cannot unlock others.
  • Store your passwords in a reputable password manager.
  • Turn on two-factor authentication wherever it is offered.

Use this tool from your AI agent

Free JSON API and Model Context Protocol (MCP) server. No signup, no API key, CORS open. Designed for Claude, ChatGPT, Cursor, scripts and frontend apps. 

curl -X POST https://mate.tools/api/v1/password-strength.php \
  -H "Content-Type: application/json" \
  -d '{"password":"correct horse battery staple"}'
import urllib.request, json

req = urllib.request.Request(
    "https://mate.tools/api/v1/password-strength.php",
    data=json.dumps({"password":"correct horse battery staple"}).encode(),
    headers={"Content-Type": "application/json"},
)
with urllib.request.urlopen(req) as r:
    print(json.load(r))
const r = await fetch("https://mate.tools/api/v1/password-strength.php", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({"password":"correct horse battery staple"}),
});
console.log(await r.json());

Add to claude_desktop_config.json (Claude Desktop), ~/.cursor/mcp.json (Cursor), or any other MCP-compatible client: 

{
  "mcpServers": {
    "mate-tools": {
      "command": "npx",
      "args": ["-y", "@mate-tools/mcp-server"]
    }
  }
}
API documentation OpenAPI 3.1 npm 60 req/min · 600 req/hour · 1 MB body cap

Frequently Asked Questions

Yes. The strength analysis runs entirely in your browser using JavaScript. Your password is never sent to any server, stored, or transmitted over the internet.

It is based on length, the variety of character types (uppercase, lowercase, numbers, symbols), estimated entropy in bits, and whether the password contains common words or predictable patterns.

A strong password is at least 12 characters long and mixes uppercase letters, lowercase letters, numbers, and symbols, while avoiding common words, sequences, and keyboard patterns.

Strong passwords help protect your accounts from unauthorized access, data breaches, and identity theft. They are your first line of defense in online security.

Change a password immediately if you suspect it has been exposed. Otherwise, a long, unique password stored in a password manager rarely needs rotating. Always use a different password for every account.

What Is a Password Strength Checker?

A password strength checker rates how hard your password would be to guess or crack, based on its length, variety of characters and whether it contains common words. Longer, more varied passwords are far stronger. Checking happens in your browser — your password is not sent anywhere.