Report a calculation or source issue
Wall Math is published by Danorie. Email contact@danorie.com: there is no contact form and no phone number, and it is a mailbox the operator reads personally.
Include the page you were on, the numbers you typed, the result you expected and why you expected it. If the disagreement is about coverage or roll size, add the product page or the wording on the label. Those four things make the run reproducible, which is the difference between a fix today and a conversation next week.
What happens next
Every report is reproduced before it is answered. If the calculator is wrong, the fix ships with the reply. If the calculator is right and the explanation was unclear, that counts as a fault too and the wording changes. If the disagreement is about a manufacturer’s figure, the source is read again and the page is dated to the day it was read.
Confirmed calculation and source errors are corrected on the page and listed on the corrections page with the date and what changed.
What this mailbox cannot do
It cannot tell you which paint or floor to buy, whether a room needs underlayment, or how to install anything. Those are product and trade questions, and answering them from a spreadsheet would be worse than not answering. It also cannot measure your room for you. A description of a room the calculators handle badly is still worth sending: the L-shaped room and closet-plus-hallway guides exist because one rectangle is not enough for many floors.
What you send, and what is kept
Do not send payment details, government identifiers or other sensitive personal data. Nothing here ever needs them. Email is kept only as long as it takes to resolve the issue and is not added to a mailing list, because there is no mailing list. What the site itself records about a visit is set out on the privacy page.
Reviewed by the operator on 2026-09-28.