Each calculator uses a tested formula
The page collects inputs and formats the output. A result names the formula version and, if we used data, the dated copy of that data. The person who maintains those engines is a builder and researcher, not a licensed advisor. That is stated on the about page instead of a fabricated credential.
Government data is stored here, not fetched as you type
We fetch an update, store it, check it, and compare it with what is already on the site. If a check fails, the last good copy stays up.
Some numbers are exact. Some are not.
A slab’s size can be exact. The number of bags you should buy is not. Cost and materials tools keep the measured number separate from waste and other planning extras.
A calculator has to do a real job
It goes live when it works and explains itself. Every tool page has a guide, FAQ, glossary, and caveats written for that calculator, not a pasted template. Long-tail examples (a state, a loan type, a year, an occupation) belong inside that guide when they are accurate. We do not generate hundreds of thin location pages from a name swap.
If something changes
If EIA, BLS, or Freddie Mac revises a figure, or we find a bug in the math, the version number changes. Older copies keep their version numbers.
Common questions about what a result is, and what it is not, are on the FAQ.