What makes a password strong?

Length is the most important factor — a 20-character random password is vastly stronger than an 8-character complex password. Avoid dictionary words, names, dates, keyboard patterns (qwerty), and common substitutions (@ for a, 3 for e).

How is password crack time calculated?

Crack time estimates assume an attacker uses optimized hardware for offline attacks (billions of guesses per second for fast hashes like MD5, thousands per second for bcrypt). Modern GPUs can test 10 billion MD5 passwords per second.

What is the zxcvbn algorithm?

zxcvbn is an open-source password strength estimator developed by Dropbox. Instead of simple rules (has uppercase? has number?), it uses pattern matching against common passwords, names, dictionary words, and keyboard patterns to estimate real-world attack resistance.

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Password Strength

Name: Password Strength
Rating: 4.8 (120 reviews)
Author: DailyDevTools

Check password strength score

Strength

Type here...

8+ characters

Includes number

Includes uppercase

Includes symbol

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What is Password Strength?

A strong password is long, unpredictable, and avoids common patterns — but 'strong' is hard to define without a scoring system. DailyDevTools' Password Strength Checker evaluates passwords using the zxcvbn algorithm, which estimates crack time based on pattern matching, dictionary attacks, and common password databases — giving you a realistic assessment rather than just checking for uppercase letters.

How to use Password Strength

1Type a password into the input field — the strength meter updates in real-time
2View the estimated crack time for different attack scenarios (offline fast hash, online throttled)
3Read the specific warnings about what makes the password weak (common words, patterns, repeated characters)
4Click Suggestions to see specific improvements recommended for your password

Frequently asked questions

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