Local · Private · Free

Password Strength Tester

Measure your password's real strength: entropy in bits, estimated crack time, and weak spots. Checked entirely on your device. Never sent anywhere.

Enter a password to test

Waiting… 0 bits of entropy

Length

Character pool

Crack time*

Your password is analyzed locally with JavaScript and never transmitted, logged, or stored. Nothing leaves this tab, close it and the password is gone. (We don't even autofill or save it.)

Checklist

How to make it stronger

How crack time is estimated

We estimate entropy as bits = length × log₂(pool size), where the pool is only the character sets you actually used (26 lowercase, 26 uppercase, 10 digits, ~33 symbols). When a common password, dictionary word, sequence, or repetition is detected, the effective entropy is reduced because an attacker would try those first.

Crack time assumes an offline attacker who has the leaked hash and guesses at 10 billion guesses/sec (a strong consumer GPU against a fast hash like unsalted SHA-1):

*This is a guide, not a guarantee. A slow, salted hash (bcrypt/argon2) would take far longer to crack; a weak reused password could fall instantly to a credential-stuffing list regardless of entropy. Use a password manager and unique passwords everywhere.

About Password Strength Tester

Password Strength Tester is a free, private tool by Digital Heroes that runs entirely in your web browser. Type any password and get an instant reading of its entropy in bits, an estimated crack time for different attacker scenarios, and a checklist of weak spots. Everything is computed locally on your device. Your password is never transmitted, logged, or stored. No sign-up or installation is required, and it keeps working offline.

What you can do

Measure entropy in bits for any password you type or paste.

See an estimated crack time across four attacker scenarios: online throttled, slow salted hash, fast GPU, and large GPU cluster.

Check a security checklist covering length, character mix, common passwords, and sequences.

Get improvement tips that explain exactly what is weakening your password and how to fix it.

Test passwords privately, nothing leaves your browser tab.

Toggle password visibility to verify what you have typed without exposing it on screen.

How to use Password Strength Tester

Open Password Strength Tester. It runs in your browser with no signup.

Type or paste a password into the input field. Results update instantly as you type.

Read the strength label, entropy score, and crack-time estimate in the stat boxes.

Review the checklist and improvement tips below to understand what to change.

Frequently asked questions

Is Password Strength Tester free?

Yes, Password Strength Tester is completely free for everyone. No sign-up, no account and no usage limits.

Is it private? Are my files uploaded anywhere?

No. Password Strength Tester runs entirely in your browser on your own device, so your data never leaves your computer and nothing is uploaded to a server.

Does it work offline?

Yes. This tool is a Progressive Web App, once the page has loaded it keeps working offline, and you can install it as an app from your browser.

Do I need to install anything or create an account?

No. Just open the page and start using it. Installing it as an app is optional and only adds offline convenience.

What does Password Strength Tester do?

It measures your password's entropy in bits, estimates how long it would take an attacker to crack, flags common passwords and weak patterns, and gives you specific tips to make it stronger. All analysis runs locally. Nothing is sent anywhere.