Password Strength Checker
Check password strength instantly — score, entropy, and security tips. 100% client-side; nothing is uploaded.
100% client-side — your data never leaves this tab
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What is Password Strength Checker?
Password Strength Checker analyzes how secure your password is — score, entropy estimate, and a checklist of security requirements. See instantly whether your password has enough length, character variety, and resistance to common patterns. Pair with our Password Generator to create strong credentials. 100% client-side: your password is never uploaded, stored, or logged.
Password analysis runs entirely in-browser; passwords are never uploaded or stored.
How to use Password Strength Checker
- 1Type or paste a password in the input field on the left.
- 2Review the strength label, score bar, and entropy estimate on the right.
- 3Check the pass/fail list for length, uppercase, lowercase, numbers, and symbols.
- 4Read suggestions to improve weak passwords before using them on important accounts.
Examples
Weak password
Fails common-password and symbol checks — rated Weak or Very Weak.
password123
Strong password
Long, mixed character sets, no common patterns — rated Strong or Very Strong.
K9#mX2@vL7!qR4
Tips & common mistakes
- Aim for 12+ characters with uppercase, lowercase, numbers, and symbols.
- Avoid dictionary words, names, and keyboard patterns like qwerty or 123456.
- Use a unique password for every account — reuse is the biggest risk even with strong passwords.
- Generate a new password with our Password Generator, then verify it here before saving.
Who uses this tool?
- Checking whether a new password meets company or website security policies.
- Teaching students and teams what makes a password strong vs weak.
- Verifying generated passwords before storing in a password manager.
- Auditing old passwords during a security cleanup or breach response.
Frequently asked questions
- How is password strength calculated?
- The checker scores length, character variety (upper, lower, numbers, symbols), and penalizes common passwords, sequential characters (abcd, 1234), and repeated patterns. Entropy estimates guessing difficulty in bits.
- Is my password sent to a server?
- No. Analysis runs entirely in your browser. Your password never leaves your device — safe even for passwords you are actively using.
- What is password entropy?
- Entropy measures randomness in bits — higher entropy means more possible combinations and longer brute-force cracking time. It is an estimate based on character pool size and length.
- Does a Strong rating mean my password is unhackable?
- No tool can guarantee that. Strong means the password resists common attacks well. Always use unique passwords, enable two-factor authentication, and store credentials in a password manager.
- How is this different from the Password Generator?
- Password Generator creates random secure passwords. Password Strength Checker evaluates passwords you already have — together they cover creation and verification.