Password Strength Checker

Check Your Password Strength — 100% in Your Browser

Type a password and get an instant, honest read on how easy it is to guess: a 0–4 strength score, an estimated time to crack, the specific weaknesses dragging it down, and concrete tips to fix them. Every calculation runs locally in your browser using a real strength-estimation engine (zxcvbn) — the same pattern-matching library used by password managers and major websites. Your password is never uploaded, saved, logged, or checked against any online breach database. Nothing leaves your device.

Unlike simplistic "add a symbol" meters that just count character types, this checker models how an attacker actually guesses: it recognizes common passwords, dictionary words, names, dates, keyboard walks (like "qwerty"), repeats, and predictable letter substitutions ("P@ssw0rd"), then estimates the real number of guesses needed. You'll see how your password holds up across four attack scenarios — from a rate-limited login form to an offline crack of a stolen database with fast hardware — because the same password can be "years" to crack in one scenario and "minutes" in another.

Use it to sanity-check a new password before you commit it, to teach yourself why length beats complexity, or to compare a random string against a multi-word passphrase. Because it works offline, it's safe to run on sensitive credentials — and the show/hide toggle lets you verify what you typed without exposing it to anyone over your shoulder.

Common Use Cases

• Vetting a new password: Before you save a password for email, banking, or work, confirm it isn't a top-10 common password or an obvious pattern.
• Building a passphrase: Watch the crack-time jump as you add words, and learn why "correct horse battery staple" beats "P@ssw0rd!".
• Security training: Show a team, in real time, exactly how quickly weak passwords fall and what makes a strong one — no theory, just live numbers.
• Auditing old habits: Test the patterns you tend to reuse (a name plus a year, a keyboard row) and see the specific warning for each.
• Meeting policy requirements: Verify a password clears length and character-class expectations before submitting it to a strict portal.

Privacy: All analysis happens locally in your browser. No password, keystroke, or result is ever transmitted to a server or a breach API — this tool has no network calls at all.