One address, read by the person who builds the site: hello@phasecalc.com.
Found a calculation that looks wrong?
Please say so. Corrections are genuinely welcome — a calculator that produces a wrong number is worse than no calculator, and an error someone reports is an error that gets fixed. If you can, include the inputs you used and the figure you expected; that turns a hunt into a five-minute fix.
Want a calculator that doesn't exist yet?
Suggestions are read and taken seriously. The tools that get built here tend to be the ones where the existing options are wrong, oversimplified, or ignore the tax treatment entirely — so if you've been through that frustration with a specific calculation, that's exactly the useful thing to describe.
No form, no ticketing system, no autoresponder. Just email.