Password generator & strength tester
Build strong random passwords and test strength, in your browser.
This password generator creates random, hard-to-guess passwords and grades the strength of any password you type in. Choose your length and which character sets to include — uppercase, lowercase, numbers, and symbols — and the tool assembles a string with enough entropy to resist brute-force and dictionary attacks. The strength meter estimates how much randomness a password contains and flags common weaknesses like short length or predictable patterns. Everything runs locally in your browser, so the passwords you generate or test are never sent anywhere.
Frequently asked questions
Are these passwords safe to use?
Yes. They are generated in your browser using your device's cryptographic random number generator and are never transmitted or stored.
What makes a password strong?
Length matters most, followed by a mix of character types. A longer passphrase often beats a short string of mixed symbols.
What does the strength score mean?
It reflects estimated entropy — roughly how many guesses an attacker would need. Higher is better, and anything flagged as weak should be replaced.
How long should a password be?
At least 12 characters for everyday accounts and 16 or more for anything sensitive. Length adds far more resistance to brute force than swapping in a few symbols.
Is a random password or a passphrase better?
A long passphrase of several random words is easier to remember and can match a shorter random string's strength, while a generated random password is denser per character. Either is strong if it has enough entropy.
Should I reuse a strong password across sites?
No. Even a strong password becomes a liability if one site is breached and you've reused it elsewhere. Use a unique password per site, ideally stored in a password manager.
More Developer utilities tools
Want this checked automatically and around the clock? Create a free SJ Monitor account and we'll alert you the moment something changes.