Contact
One inbox, read by a human (Thomas Empl). Corrections get answered first.
We aim to reply within a few business days. There is no phone line and no contact form — email keeps a written record of the numbers involved, which matters when the subject is a calculation.
Reporting an incorrect number
This is the message we most want to receive. A wrong estimate costs a reader real money, so please include enough to reproduce it:
- The page URL (for example
/concrete-calculator/12x12-slab/) - The exact inputs you entered — dimensions, thickness or depth, coats, bag size, waste %
- The number the page showed and the number you expected
- Your source, if you have one — a data sheet, a supplier quote, or your own arithmetic
We re-derive the figure from the source constants, and if the page is wrong we fix it, add a regression test so it can’t come back, and update the page’s “last updated” date. If the page is right, we’ll write back and show the working — often the difference is a waste factor or a rounding rule that a supplier applies differently. How we arrive at each figure is documented in How we calculate.
Suggesting a calculator or guide
We add tools where the unit conversion is genuinely annoying — that’s the filter. Tell us what you were trying to estimate, what you had to work out by hand, and where the existing tools let you down. Requests that describe a real project beat generic topic suggestions every time.
Advertising, partnerships and affiliates
We run display advertising and use affiliate or partner links to retailers and contractor-matching services. What we don’t sell is editorial influence: no sponsored guides, no paid placement inside a calculator, no link insertions into existing articles, and no adjusting a recommendation to favour a partner. Pitches along those lines are declined. Everything else is welcome at the address above; see how the site is funded for the full position.
Privacy requests
To ask what data is held about you, request deletion, or opt out of the sale or sharing of personal information, email us with “Privacy request” in the subject line. Include the email address you want us to search against. Details of what is and isn’t collected — and the direct Google opt-out links, which are usually faster than writing to us — are in the privacy policy.
What we can’t help with
We can’t size a structural slab, review a design, interpret your local building code, or tell you whether a specific contractor’s quote is fair. Those need a licensed professional who can see the site. What we can do is make sure the arithmetic on this site is right — see the terms and disclaimer for the boundary.