Password Strength Checker
See how strong your password really is. Type a password and this password strength checker returns the bits of entropy, a strength score and a rating — plus clear, actionable suggestions to make it harder to crack. It all runs privately in your browser, so your password never leaves your device.
Analyzed locally — your password is never sent anywhere.
What is a password strength checker?
A password strength checker estimates how hard a password would be to crack by measuring its entropy, expressed in bits. Entropy reflects how many guesses an attacker would need: every extra bit roughly doubles the number of possible combinations. The checker starts by identifying which character types are present — lowercase, uppercase, numbers and symbols — to estimate the size of the character set, then multiplies that by the password's length. A 12-character lowercase password has a smaller character set than the same length with upper case, numbers and symbols, so it carries less entropy.
Real attackers do not just brute force every combination; they try common words, names, sequences and previously leaked passwords first. A good strength checker also flags those tell-tale patterns and downgrades the score. The result is a rating from Very weak to Very strong, alongside a rough time-to-crack figure and concrete suggestions — such as adding length, mixing character types, or avoiding dictionary words.
Because the analysis happens on your device, you can test a password without ever risking it being sent or stored.
How to use the password strength checker
- Type or paste a password into the Password field.
- Read the entropy in bits and the strength rating that update as you type.
- Review the Time to crack estimate to understand the risk level.
- Follow the suggestions to strengthen the password, then test it again.
Example
Enter password and the checker flags it as Very weak with well under 30 bits of entropy, because it is a common dictionary word. Now enter Tr0ub4d0r&M3l0dy — around 15 characters mixing cases, numbers and symbols — and the score jumps to tens of bits, rating it Strong. Adding just a few extra characters raises the effective strength far more than swapping one symbol for another.
Common use cases
- Checking that a new account password is strong enough before you save it.
- Auditing whether existing passwords meet your company's security policy.
- Comparing password ideas to pick the hardest-to-guess option.
- Teaching staff or students what makes a password secure.
Pro tips
- Favour length over complexity — a long passphrase beats a short jumble of symbols.
- Use a unique password per account so one breach does not spread.
- Turn on two-factor authentication wherever it is offered.
- Never reuse an important password across email, banking or work.
FAQ
What is password entropy?
Entropy measures how many guesses an attacker would need, in bits. Each extra bit roughly doubles the guessing effort.
How much entropy is a strong password?
Roughly 60 bits is reasonable for most accounts and 80 bits or more is strong. Aim for at least 12 characters of mixed types.
Is this password checker private?
Yes. The analysis runs entirely in your browser and your password is never uploaded or stored.
What makes a password weak?
Short length, common words, names, dates, obvious sequences like 1234, and repeated characters all reduce strength dramatically.
Should I reuse passwords across sites?
No. If one site is breached, an attacker can try the same password elsewhere. Use a unique password for every account.
How often should I change my password?
Only when a site reports a breach. Otherwise, a long unique password and two-factor authentication are better than frequent changes.
What is two-factor authentication?
It adds a second proof of identity, such as a code from an app, so a stolen password alone is not enough to log in.
Does a longer password always mean a stronger one?
Usually yes, but only if it is not a common phrase or predictable pattern. Random passphrases are strong and hard to guess.
Are symbols needed for a strong password?
Symbols add entropy, but length matters more. A long password of mixed lowercase letters is often stronger than a short one with symbols.
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