Password Entropy Calculator
Estimate password strength in bits from its length and the size of the character set it draws from. Enter password length and character set size to…
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Estimate password strength in bits from its length and the size of the character set it draws from. Enter password length and character set size to see entropy when you calculate.
Worked example
Example calculated from the starting values. Enter your own values and press Calculate to get your result.
With the default inputs (password length = 12, character set size = 72), the results are: entropy 74.0 bits.
Quick reference: password length vs result
Reference table based on the example values; it is not your calculation result.
| Password length | Entropy |
|---|---|
| 6 | 37.0 bits |
| 12 | 74.0 bits |
| 24 | 148.1 bits |
| 60 | 370.2 bits |
| 120 | 740.4 bits |
| 240 | 1,480.8 bits |
Frequently asked questions
What formula does this calculator use?
Entropy = len × ln(cs) ÷ ln(2). Variables: len = password length, cs = character set size.
What do I need to enter?
You need password length, character set size. Results update as you type.
What is an example result?
With the default inputs (password length = 12, character set size = 72), the results are: entropy 74.0 bits.