Password Strength Checker

Analyze your password strength instantly — runs in your browser, never sent to any server

Your password is never sent anywhere — all analysis happens locally.

Type a password above to see its strength analysis

What Makes a Password Strong?

A strong password is one that is computationally difficult to guess or crack. Modern security research shows that length is the single most important factor — a 20-character passphrase made of random words is stronger than an 8-character mix of symbols and numbers.

This checker analyzes your password for entropy (the measure of unpredictability), character variety, length, and common patterns. All analysis happens in your browser — your password is never sent to any server.

Password Strength Guidelines

Length (most important)

Aim for at least 12 characters. 16+ is ideal. A 12-character random password has over 2^72 combinations with mixed case and numbers.

Uppercase & Lowercase

Mixing upper and lowercase letters significantly increases the character pool from 26 to 52 per position.

Numbers

Adding digits expands the pool further. Avoid predictable number patterns like birth years or 1234.

Special Characters

!@#$%^&*() and similar characters expand the pool significantly. Avoid using only @ or 1 as easy substitutions.

No dictionary words

Dictionary attacks try common words and variations first. Avoid names, places, and common words as standalone passwords.

Unique per site

Even the strongest password becomes a liability if reused. Use a password manager to generate and store unique passwords.

Frequently Asked Questions

Is my password sent anywhere?
No. This tool runs entirely in your browser using JavaScript. Your password never leaves your device. We do not log, store, or transmit any input.
What is password entropy?
Entropy measures how unpredictable a password is, expressed in bits. It is calculated as log₂(pool_size ^ length). A 12-character password using all character types has roughly 79 bits of entropy — considered very strong.
What is a good password entropy?
Above 60 bits is considered strong for most purposes. Above 80 bits is very strong. Government and financial systems typically require 80+ bits.
How long would it take to crack my password?
A modern GPU can attempt ~10 billion guesses per second. An 8-character all-lowercase password has only 26^8 ≈ 208 billion combinations — crackable in under a minute. A 16-character password with mixed characters has more combinations than atoms in the observable universe.

Popular searches: password strength checker • how strong is my password • password security test • check password strength online • password entropy calculator