Password Strength Checker — Crack Time & Security Score

By CalcMesh Editorial · Reviewed against primary-source formulas

Password Security Guide

Password Best Practices

Length over complexity: A 16-character password with only lowercase letters has more entropy than a random 8-character password with all character types.
Unique per site: Never reuse passwords. If one account is breached, all accounts with the same password are compromised.
Avoid personal info: Names, birthdays, pet names, and addresses are among the first things attackers try.
No common patterns: Avoid "Password1!", "qwerty", "abc123", and keyboard patterns like "zxcvbn".

The Passphrase Approach

Instead of a complex password like "J#7kQ!9m", consider a passphrase of 4-6 random words:

"maple-candle-orbit-frozen" (easy to remember, very strong)
"correct horse battery staple" (the classic XKCD example)

Random word passphrases are both stronger and easier to remember than short complex passwords. The key is using truly random words, not song lyrics or famous quotes.

Password Managers

A password manager is the best way to maintain unique, strong passwords for every account. Recommended options:

1Password: User-friendly, family sharing, travel mode
Bitwarden: Open source, free tier available
KeePassXC: Fully offline, open source

Enable Two-Factor Authentication

Even a strong password can be stolen in a data breach. Two-factor authentication (2FA) adds a second layer of security. Prefer authenticator apps (like Authy or Google Authenticator) over SMS codes, as SMS can be intercepted via SIM swapping.

Note: This tool provides a rough estimate of password strength. Real-world attack resistance depends on the hashing algorithm used by the service and the attacker's resources.

Password Cracking in 2024

Hive Systems' 2024 Password Table calculated hash-crack times on a 12x RTX 4090 rig against bcrypt($2b$11): 8-character all-lowercase passwords fall in 7 minutes, 10-character mixed-case in 5 months, 12-character mixed-case+numbers in 26,000 years. But if the site uses weaker MD5 hashing, the same 12-character password falls in 1 hour — attack time depends hugely on the hash algorithm the breached service used.

NIST Special Publication 800-63B (2023 revision) dropped mandatory periodic password changes and character-class requirements in favor of length (≥12 characters), dictionary checking, and known-breach checking. Have I Been Pwned's database as of 2024 tracked 13.4 billion compromised credentials across 850+ breaches — any password appearing there is already burned regardless of its complexity score.

Password manager adoption surged 40% between 2020 and 2023 (NordPass global survey, 18,000 respondents) yet only 28% of U.S. adults use one — 63% still reuse passwords across sites. The median U.S. adult has 100+ password-protected accounts per Dashlane 2023 data, far exceeding human memorable-password capacity. Passkeys (FIDO2/WebAuthn) are growing fast: Google reports 800 million+ passkey authentications in 2023, with sign-in success rates 2-4x higher than passwords and phishing-resistant by design.

Sources: Hive Systems 2024 Password Table, NIST SP 800-63B, Have I Been Pwned, Google passkey report

Methodology & Assumptions

This calculator implements standard formulas drawn from primary-source authorities. Values are point-in-time estimates; consult a licensed professional for high-stakes decisions. See the per-input definitions and source citations below.

How this works

Computations are deterministic and run client-side — no inputs leave your browser. Formulas are derived from standard published formulas for the calculator's domain (mortgage, taxes, energy, conversions, etc.). When the underlying agency publishes updated rates or thresholds we refresh defaults and update the page's lastmod timestamp.

Frequently Asked Questions

Is it safe to type my password into this tool?

Yes. This tool runs entirely in your browser using JavaScript. Your password is never sent to any server, never stored, and never leaves your device. You can verify this by disconnecting from the internet and using the tool — it works completely offline. The source code is visible in your browser developer tools for full transparency.

What makes a strong password?

A strong password has at least 12 characters and combines uppercase letters, lowercase letters, numbers, and special symbols. Length is the single most important factor — a 16-character password with just lowercase letters is often stronger than an 8-character password with all character types. Avoid dictionary words, personal information, and common patterns like "123" or "abc".

Should I use a passphrase instead of a password?

Passphrases (such as "correct-horse-battery-staple") are an excellent approach. They are longer, easier to remember, and can be very strong. A 4-word passphrase from a large word list provides about 44 bits of entropy per word, making it comparable to a random 12-character password. The key is using truly random words, not a meaningful sentence.

Do I need a password manager?

A password manager is strongly recommended. It generates unique, strong passwords for every account and remembers them for you. This means you only need to memorize one master password. Reusing passwords across sites is one of the biggest security risks — if one site is breached, attackers try those credentials on other sites. Popular options include 1Password, Bitwarden, and KeePassXC.