Is my password sent to a server?

No. All analysis runs entirely in your browser using JavaScript. Your password is never transmitted over the network, logged, or stored anywhere.

What does entropy in bits mean?

Entropy measures how unpredictable a password is. It is calculated as log2(pool size) × password length, where pool size is the number of distinct character types used. A password with 60+ bits of entropy is considered strong against brute-force attacks.

Why does my password show as a common password?

The tool checks your input against a built-in list of the 100 most frequently used passwords. If your password appears on that list, it can be cracked almost instantly regardless of its length.

What strength level should I aim for?

Aim for Strong or Very Strong. These levels correspond to roughly 60 or more bits of entropy. A combination of uppercase, lowercase, digits, symbols, and a length of at least 12 characters typically achieves this.

Password Strength Meter

Type a password and instantly see its strength score, entropy in bits, character class breakdown, and actionable improvement tips — all processed locally in your browser.

A password strength meter estimates how hard a password is to guess.

Enter Your Password

Strength —

Entropy — bits

Character Classes

Lowercase letters (a–z)
Uppercase letters (A–Z)
Digits (0–9)
Symbols (!@#$%…)
Length at least 12 characters

Recommendations

Type a password to see recommendations

How strength is calculated

1 Entropy: log₂(pool) × length — the core measure of unpredictability.

2 Character pool: expands from 26 (lowercase only) up to 95 (all ASCII printable).

3 Penalties: repeated characters, sequential runs, and common patterns reduce the score.

4 Common list: exact match against the top 100 passwords forces the score to Very Weak.

Quick answer

A password strength meter estimates how hard a password is to guess. This one computes entropy as log2(character pool) × length, lowers the score for repeats, sequences and keyboard walks, and rates the result from Very Weak to Very Strong; any top-100 common password is Very Weak.

Examples

Password	Entropy	Rating
8 lowercase letters, no patterns	37.6 bits	Weak
12 mixed-case letters + digits, no patterns	71.5 bits	Strong
16 characters, all 4 classes	105.1 bits	Very Strong
"sunshine" (common list)	37.6 bits	Very Weak

Type a password for live entropy, rating and tips; it never leaves your browser.

Summary

This tool scores password strength in real time. It measures entropy in bits, checks which character classes are present, flags common passwords and predictable patterns, and lists concrete steps to make a weak password stronger. Everything runs in your browser.

How it works

Type or paste your password into the input field.
The strength bar updates instantly showing one of five levels: Very Weak, Weak, Fair, Strong, or Very Strong.
Check the entropy display to see the calculated bits of randomness.
Review the character class checklist to see which criteria your password satisfies.
Read the recommendations list to learn specific steps to make your password stronger.

Use cases

Evaluate whether a new account password meets a strong security standard before using it.
Audit existing passwords during a personal security review.
Teach users about password construction and entropy during security awareness training.

Frequently Asked Questions

Last updated: 2026-06-13 · Reviewed by Nham Vu