Developer tools
Password Strength Calculator
Estimate password strength from length and character variety with entropy and crack-time estimates locally in your browser.
Type a password to estimate its strength from length and character variety. The check runs locally in your browser; your password is not uploaded or stored.
Check a password without sending it anywhere.
Type a password to estimate its strength from length and character variety. The result shows a 0 to 4 score, estimated entropy in bits, offline and online crack-time estimates, and concrete ways to strengthen it. Everything runs locally in your browser, so your password is not uploaded or stored.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What does the password strength calculator show?
Type a password to see a strength score from 0 to 4 with a label from Very weak to Very strong, the estimated entropy in bits from password length times log2 of the character pool, and offline and online crack-time estimates. For example, a 12-character password using lowercase, uppercase, digits, and symbols has about 79 bits of entropy and rates Strong.
How is password entropy estimated?
Entropy is password length multiplied by log2 of the character pool: 26 for lowercase, 26 more for uppercase, 10 for digits, 32 for symbols, and 100 more when other Unicode characters appear. Very common passwords such as password or qwerty are capped at Weak even when the math looks better, because attackers try them first.
Which inputs are accepted?
Enter a single-line password with 1 to 256 characters. Empty passwords and passwords with line breaks show a clear error instead of a result.
Does my password stay private?
Yes. The strength check and copy action run locally in your browser. CodeASystem does not upload or store the password you type.