Password Strength Checker — Fast, Private, Client-Side

Why Strong Passwords Still Matter (and What’s Next)

A strong password is your first and often only line of defense against account takeover. Most breaches don’t involve “movie-style hacking”; they start with credential stuffing (attackers try passwords leaked from other sites), weak or reused passwords, phishing, or brute forcing simple patterns like Summer2024!. The goal of a strong password is to be hard to guess both by humans and by automated tools, and unique so that one breach doesn’t unlock everything else.

What makes a password “strong”?

• Length first: Aim for 12–16+ characters. Longer passphrases (e.g., several unrelated words) resist guessing better than short, complex strings.
• Unpredictability: Avoid common words, keyboard runs (qwerty), dates, names, and simple substitutions (P@ssw0rd).
• Uniqueness: Never reuse a password across services. If one site is breached, attackers will try those credentials elsewhere.

Use a password manager & turn on MFA

Password managers generate and store long, unique passwords for every account—so you only remember one strong master password (or use a passkey/biometric). Combine this with multi-factor authentication (MFA) wherever available. Even if a password leaks, an attacker still has to pass an extra barrier like a one-time code, authenticator app, or hardware key.

“Sign in with Google/Apple” and passkeys

Using a trusted identity provider (e.g., Sign in with Google) can reduce password sprawl. You delegate login to an account you protect well (with MFA and alerts), and the site never stores your password. An even more modern option is passkeys (FIDO2/WebAuthn), which replace passwords with public-key cryptography tied to your device, resistant to phishing and credential stuffing. Where supported, passkeys are a strong, user-friendly choice.

A quick note on “post-quantum” security

Large-scale quantum computers could threaten some public-key algorithms (like RSA and classic elliptic-curve cryptography), which are used for things such as TLS certificates and some login protocols. Password security is a bit different: websites should store passwords using slow, salted hash functions (e.g., bcrypt, scrypt, Argon2) designed to frustrate offline cracking—even with powerful hardware. While quantum advances are being addressed with post-quantum cryptography for key exchange and signatures, the practical takeaway for users remains the same: choose strong, unique passwords (or passkeys) and enable MFA. Doing this dramatically reduces risk today and sets you up well for tomorrow’s cryptography upgrades.

Practical tips you can apply right now

• Create a long passphrase from unrelated words (e.g., “violin-pebble-daylight-canoe”).
• Store it in a reputable password manager; let it generate unique ones for other sites.
• Turn on MFA everywhere—prefer app-based or hardware keys over SMS where possible.
• Consider sign-in options like Sign in with Google or passkeys to reduce password reuse and phishing exposure.
• Change weak or reused passwords first on email, banking, and primary identity accounts.

This checker runs entirely in your browser—no passwords are uploaded. Results are estimates to help you spot obvious weaknesses. Real-world security also depends on the site’s hashing scheme, rate limits, breach history, and whether you use MFA or passkeys.