Password Strength Meter
Check how strong a password is and estimate time to crack it.
Checked entirely in your browser — never sent anywhere.
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How it works
Type a password and the tool estimates its strength from length and the variety of character types used (lowercase, uppercase, digits, symbols). It calculates entropy in bits — each character drawn from a larger pool adds more — and translates that into a rough time-to-crack estimate against fast offline guessing, plus a strength rating. It also flags obvious weaknesses like being too short. The password is checked entirely in your browser and never sent anywhere or stored.
entropy bits = length × log2(poolSize)
Common use cases
- Checking whether a new password is strong enough before using it.
- Understanding why length matters more than swapping letters for symbols.
- Teaching good password habits with concrete crack-time estimates.
Frequently asked questions
Is my password sent anywhere?
No. Strength is calculated entirely in your browser. The password is never transmitted, logged, or stored, so it is safe to test a real one.
How is crack time estimated?
From the entropy in bits, assuming a fast offline attacker making billions of guesses per second. It is an order-of-magnitude estimate, not a guarantee — real attacks vary widely.
What makes a password strong?
Length first, then variety. A long passphrase usually beats a short complex string. Avoid dictionary words, names, and reused passwords — use the Password Generator for strong random ones.