Password Entropy Calculator
Estimate password entropy from length and character sets.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
Password Entropy Calculator
How to use this tool
- Enter your values in the fields above.
- Press Generate to see the result.
- Use Load sample to try the worked example, Copy result to copy it, or Clear to start again.
Worked example
Password Password1! (10 characters, all four sets, pool 94) gives 65.5 bits, a moderate estimate.
What this tool does not do / Limits
This gives a mathematical estimate only. It does not check whether a password has leaked, is reused, or is guessable from personal details.
Frequently asked questions
Is my password sent anywhere?
No. It is measured in this browser and never leaves the page.
Does high entropy mean it is safe?
Not on its own. A leaked or reused password is unsafe even with high entropy.
Related tools
JSON Studio
Format, validate, minify, query and compare JSON in your browser, with precise line-and-column errors.
LiveRegex Tester
Test patterns against sample text with match highlighting, capture groups and a safe one-second timeout.
LiveSecurity Header and DNS Checker
Check HSTS, CSP and other security headers, TLS details, and DNS/email authentication records (SPF, DKIM, DMARC).
Live