100% Private — Runs in Your Browser

Password Strength Checker
Free & Secure

Instantly check how strong your password is. No sign-up, no servers, no tracking. Your password never leaves your device.

No Data Stored Real-Time Analysis Completely Free Works Offline

🔐 Check Your Password Now

Enter your password to check its strength

Length

—

characters

Character Types

—

out of 4 categories

Entropy

—

bits of randomness

Crack Time

—

at 10B guesses/sec

Length ≥ 12 characters

Uppercase letters (A–Z)

Lowercase letters (a–z)

Numbers (0–9)

Special characters (!@#$…)

Not a common password

No sequential patterns (abc, 123)

No keyboard patterns (qwerty)

How to improve your password

Why PasswordScan

Built for Privacy & Precision

Everything you need to evaluate password strength — with zero risk to your data.

100% Private

Your password never leaves your device. Analysis runs entirely in your browser — no server, no logs, no tracking.

Real-Time Analysis

Score updates instantly as you type — no button clicks, no loading spinners, no waiting at all.

Smart Scoring Engine

Checks length, entropy, character variety, common passwords, sequential and keyboard patterns.

Works Offline

No internet needed. The entire engine is pure JavaScript — disconnect and it still works perfectly.

Detailed Breakdown

Score, crack time estimate, entropy in bits, character variety, and a full pass/fail security checklist.

Always Free

No sign-up, no paywall, no premium tier. Open source and free to use forever — for everyone.

FAQ

Frequently Asked Questions

Everything you need to know about password strength and how our checker works.

Is my password stored or sent anywhere?

No. PasswordScan runs entirely in your browser using JavaScript. Your password is never sent to any server, stored in any database, or transmitted over the internet. Everything happens locally on your device. You can even disconnect from the internet and the tool will still work.

How is the password strength score calculated?

The score (0–100) analyzes: password length (longer = better), character variety (uppercase, lowercase, numbers, symbols), mathematical entropy (bits of randomness), and applies penalties for common passwords, sequential patterns like "abc" or "123", keyboard patterns like "qwerty", and repeated characters.

What makes a password strong?

A strong password has at least 12–16 characters and uses a mix of uppercase letters (A–Z), lowercase letters (a–z), numbers (0–9), and special symbols (!@#$%). It avoids dictionary words, common patterns, and personal information like your name or birthday.

What does the crack time estimate mean?

The crack time estimates how long it would take a powerful computer making 10 billion guesses per second to crack your password through brute force. This is based on the password's entropy — the mathematical measure of unpredictability. A password taking "centuries" to crack is considered very secure.

What is password entropy?

Entropy, measured in bits, quantifies how unpredictable a password is. It's calculated from the size of the character set used and the length of the password. A password with 60+ bits of entropy is generally considered strong. For example, a 16-character password using all four character types has around 104 bits of entropy.

Should I use a password manager?

Absolutely. Password managers like Bitwarden (free & open source), 1Password, and Dashlane help you create and securely store unique, strong passwords for every account. This is the single most effective step you can take to improve your online security. Read: Is a password manager safe?

How often should I change my password?

Modern security guidelines (from NIST) no longer recommend changing passwords on a fixed schedule. Instead, change your password if: you suspect a breach, you've been notified of a data leak, or you've used the same password on multiple sites. Use a password manager to use unique passwords everywhere.

Is a longer password always better?

Yes — length is the single most impactful factor in password strength. A 20-character password using only lowercase letters is often stronger than a 10-character password with all four character types. Ideally, aim for both length and variety. A 16+ character password mixing all types is extremely strong.

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