For your consideration, one does not need to have their password manager online to use HIBP; they offer [at least] two different concessions to your concerns:

For your consideration, one does not need to have their password manager online to use HIBP; they offer [at least] two different concessions to your concerns: - SHA1 or NTLM hash prefix matching https://haveibeenpwned.com/API/v3#SearchingPwnedPasswordsByRange https://haveibeenpwned.com/API/v3#SearchingPwnedPasswordsByR... - actually download the HIBP db and check for yourself https://haveibeenpwned.com/API/v3#PwnedPasswordsDownload https://haveibeenpwned.com/API/v3#PwnedPasswordsDownload Thus you could hash your passwords in your airgapped setup, transfer the hashes using a mechanism you trust to an Internet connected device, and then check the hashes