Password Strength Checker
Check how strong a password is, entirely in your browser.
This is an estimate based on length and character variety, assuming a fast offline attack (about 10 billion guesses per second). It does not check whether a password has appeared in a known breach. Use a long, unique password and a password manager.
Recommended next steps
Related tools
Generate random integers within a chosen range using your browser's cryptographic random source.
Count words, characters, sentences, paragraphs, and reading time as you type.
Create a QR code from any text or link and download it as PNG or SVG.
Frequently asked questions
No. The checker runs entirely in your browser using JavaScript. Your password is never uploaded to a server, logged, or stored, so it is safe to test a real password you use.
We estimate entropy as the password length multiplied by log2 of the character-pool size (lowercase, uppercase, digits, and symbols each add to the pool). More length and more character types mean higher entropy and a stronger rating. It is an estimate, not a guarantee.
It is a rough estimate of how long a fast offline attack — around 10 billion guesses per second — would take to find the password by brute force, on average. Real-world attacks vary widely, and a password found in a data breach can be cracked instantly regardless of this figure.
Not on its own. This tool only measures length and character variety; it does not know if your password is a common word, a known breached password, or reused across sites. For real safety, use a long, unique, randomly generated password and a password manager.
Last updated 2026-06-23.