Contact
Questions, corrections and suggestions are all welcome at hello@homebrewnumbers.com.
Reporting a wrong number
These are the most useful messages to receive, and they get priority. If you can include the inputs you used, what the calculator returned, and what you expected instead, the problem can usually be reproduced immediately. If your expected value comes from a published source, a link to it settles the question outright.
Sources for the missing calculators
Several calculators are missing because their formulas could not be retrieved from a published source — Rager bitterness, strike water and mash infusion, hydrometer temperature correction, keg carbonation pressure, and refractometer correction. The About page explains each one. If you know where any of them is properly documented, send the reference and it will get built.