About this password strength checker
Estimate how strong a password is from its length and character variety, without ever sending it anywhere. Type or paste a password, and this tool detects which character types it uses — lowercase, uppercase, numbers, and symbols — estimates its entropy in bits from that character pool and length, and labels it Weak, Fair, Good, or Strong against common entropy thresholds. Use this workspace to prepare a result you can review before putting it to use. All processing takes place on your device, without an account or an upload of your inputs. Check the examples to understand the expected output, read the limitations for the supported scope, and reset the form when you want to start a separate task.
How the password strength checker works
Entropy (bits) = length × log2(character pool size), where pool size adds 26 for lowercase, 26 for uppercase, 10 for digits, and 33 for symbols found in the password. Below 28 bits is Weak, below 36 is Fair, below 60 is Good, and 60 or above is Strong.
Password Strength Checker examples
"abc"
Weak (≈14.1 bits)
"Tr0ub4dor&3"
Strong (≈72.3 bits)
Limitations & privacy
Maximum 1,024 characters. Character-pool entropy assumes independent random choices and can overrate human-chosen text. Common and repeated patterns are flagged by a small local list; breached passwords are not checked. A strong label does not guarantee safety.
Inputs and results stay in this browser. Only tool identifiers are stored for your recently used tools. You can clear that history from the directory.
Password Strength Checker: frequently asked questions
How does the password strength checker work?
Entropy (bits) = length × log2(character pool size), where pool size adds 26 for lowercase, 26 for uppercase, 10 for digits, and 33 for symbols found in the password. Below 28 bits is Weak, below 36 is Fair, below 60 is Good, and 60 or above is Strong.
What can I inspect in the password strength checker result?
Inspect length, distinct characters, repeated runs and common patterns alongside the entropy estimate. Maximum 1,024 characters. Character-pool entropy assumes independent random choices and can overrate human-chosen text. Common and repeated patterns are flagged by a small local list; breached passwords are not checked. A strong label does not guarantee safety.
Does the password strength checker upload my input?
Processing happens in your browser. No tool input or output is uploaded to a server. Use Reset to clear the current workspace before starting a separate task.
Updated September 20, 2026