Your account
Give an address and we send a link that signs you in once.
What an account changes about what we store.
Everywhere else on this site, the most identifying thing kept is a checksum and a birth year. An account stores your email address, which identifies you directly. It buys one thing: coming back to a chart, and a record that accumulates instead of resetting. If that is not worth it to you, every calculator here works without one and always will.
What we keep.