Email is the whole contact system. The only form on the site is the contractor quote request on cost pages; everything else comes to this address.
Reporting a wrong result
Include the calculator name, the exact inputs (with units) and what you expected. Most reports are checked against the published formula and source data within a few days, and fixes ship to the live site the same day they are verified.
Requesting a calculator
Tell us the material, how it is sold (tons, yards, bags, sheets, sticks) and the density or yield your supplier quotes. Calculators that only need existing math usually ship within a week.
Advertising, affiliates and embedding
Ad placements are handled through a network, not sold directly. If you would like to embed a calculator on your own site, or license the calculation library, write to the same address.