Password Strength Checker
Type or paste a password below to see a live breakdown of its strength — length, character variety, estimated entropy and a rough crack-time estimate. Your password is never sent anywhere; every calculation happens instantly inside your own browser.
How to Use the Password Strength Checker
- Type or paste a password into the field (click "Show" to reveal the characters if you want to double-check it).
- Watch the meter, entropy score and character-variety checklist update instantly as you type.
- Check the estimated crack time bucket to get a feel for how resistant the password is to guessing attacks.
- Adjust length and character mix, then re-check, until you reach "Strong".
Why Use This Tool?
Is my password transmitted or stored anywhere?
No. Everything on this page runs client-side in JavaScript. Your password is never sent over the network, never logged, and disappears the moment you refresh or close the tab. You can even disconnect from the internet after loading the page and it will still work perfectly.
What does "entropy" mean?
Entropy is a measure of unpredictability, expressed in bits. It's calculated as length × log₂(character set size) — the more character types you use and the longer the password, the higher the entropy, and the more attempts an attacker would statistically need to guess it.
How accurate is the crack time estimate?
The crack time is a rough estimate assuming a determined offline brute-force attack at a fixed guesses-per-second rate. Real-world results vary hugely depending on the attacker's hardware, the hashing algorithm protecting the password on the target service, and whether the password appears in known leaked-password lists (which can make even a long password crackable instantly). Treat the result as a directional guide, not a guarantee.
What's the single best way to improve a weak result?
Length matters more than complexity tricks. Adding a few extra characters increases entropy far more than swapping a letter for a symbol. Consider our Passphrase Generator for a password that's both long and easy to remember.