Password Strength Calculator
Fill in the values and the answer updates as you type.
How the Password Strength Calculator works
Entropy = length × log2(size of character set). It assumes every character is chosen at random. Real passwords made of words or patterns are weaker than the number suggests. Use a password manager and longer random passwords.
Inputs and results
The Password Strength Calculator takes 2 inputs and gives 3 results.
What you enter
- Password length (characters) — starts at 12.
- Character set — starts at Letters and digits (62). Choose from: Digits only (10), Lowercase letters (26), Letters, mixed case (52), Letters and digits (62) and All keyboard symbols (94).
What you get
- Entropy (bits)
- Strength
- Possible combinations
Example: Password Strength Calculator with the starting values
With password length 12 characters and character set Letters and digits (62), the calculator returns:
| Entropy (bits) | 71.5 |
|---|---|
| Strength | Strong |
| Possible combinations | about 10^21.5 |
Change any value above and the results update straight away.
Password Strength Calculator FAQ
How do I use the Password Strength Calculator?
Enter password length and character set in the fields, then read entropy (bits), strength and possible combinations in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Password Strength Calculator calculate?
Estimate password entropy from its length and character set. It returns entropy (bits), strength and possible combinations from the 2 values you provide.
What values does the Password Strength Calculator start with?
It opens with password length 12 characters and character set Letters and digits (62) so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Password Strength Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Password Strength Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.