How it works
Check patterns, not promises
The locally bundled zxcvbn-ts estimator looks for familiar words, repetition, keyboard patterns and other guessable structures. It produces a qualitative 0–4 estimate. It does not query a breach database.
Use a similar example rather than an important existing password. The limit is 256 Unicode code points and 1,024 UTF-8 bytes; oversized input is not silently shortened for scoring. Empty input has no score.
What happens to your input?
This tool does its work on this page. The site does not submit your entries or results or keep a history. However, any script allowed to run on the page could read its fields. Clearing the tool or leaving the page cannot erase clipboard entries, downloads, printouts, or screenshots. It also cannot protect you if your browser or device is compromised. Read the privacy limits.