Password strength checker

Free · no sign-up

See how strong a password is — its entropy and a rough crack time. Nothing is sent anywhere.

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Entropy

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Estimated crack time

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Length

a–zA–Z0–9!@#

Checked entirely in your browser — the password never leaves your device.

Check how strong a password is before you rely on it. Type or paste it and see the estimated entropy in bits, a rough crack time, and which character types it uses. Everything runs in your browser — the password is never sent anywhere. Free, no sign-up.

✓Entropy estimate in bits
✓Rough time-to-crack
✓Character sets used (a–z, A–Z, 0–9, symbols)
✓Live strength meter
✓Runs in your browser — nothing uploaded

Who it's for

Checking a password before using it
Teaching good password habits
Comparing two passwords
Deciding if a password needs replacing

How it works

1Type or paste your password.
2Read the strength and entropy.
3See the estimated crack time.
4Add length or symbols to improve it.

Frequently asked questions

What makes a password strong?+

Length and randomness, far more than symbols. Every extra character multiplies the possibilities; a long random password beats a short 'complex' one. Aim for 16+ characters.

How is the strength estimated?+

From entropy: the character-set size and the length give an estimate in bits of how unpredictable the password is. It's a guide — a real attacker's dictionaries and patterns can do better against invented passwords.

Is my password sent anywhere?+

No. Everything is computed locally in your browser; the password never leaves your device.