The Password Strength Checker evaluates local heuristics. It cannot know an attacker’s resources, a service’s hashing settings, rate limits or whether a password has leaked.
Understand the entropy formula
For uniformly random independent characters from N symbols, length L has L × log2(N) bits of selection entropy. Sixteen characters chosen uniformly from 64 symbols give 96 bits. The same formula does not describe a human phrase merely because it contains several character classes.
Predictable substitutions and appended years do not make a familiar word random. A tool can overstate strength when it counts the possible alphabet but ignores how the string was chosen.
Use the score appropriately
Test invented strings, not a credential you depend on. Distinguish search-space size from a crack-time estimate, which requires a stated guessing rate and storage model.
Use unique credentials, a trustworthy password manager and available multifactor authentication. A local score is feedback about a string, not a breach check or security certification. No password is made “uncrackable” by a green indicator.