Contact
Everything here is written and maintained byArthur Kingsfield — see about — and email reaches me directly. There is no form, because the site is entirely static and has no server to submit one to.
Reporting a mistake
This is the message I most want to get. If a result looks wrong, please include the calculator name, the exact inputs you used including the units, and what you expected instead. That is usually enough to reproduce it immediately; without the inputs I am guessing.
What happens next is described in more detail on thehow we verify page, but briefly: a confirmed error is fixed and a new assertion is added to the build so that the same mistake cannot reappear later. Corrections are the highest priority thing in the queue and usually go live within a day or two. If a report turns out to be a difference of assumption rather than an error — a different standard, a different rounding convention — I will say so and, where it helps, add a note to the page explaining which convention it follows.
Requesting a calculator
Requests are genuinely welcome and several of the tools here exist because somebody asked for them. The ones that work best are specific: a named calculation, ideally with the formula or the standard it should follow, and a sentence about what you would use it for. That last part matters more than it sounds — knowing whether a tool is for a hobbyist, a student, or someone doing it professionally changes which inputs belong on the page and which assumptions need spelling out.
What I can't help with
I cannot check your specific design, prescription, structure, or financial decision, and I am not able to act as a consultant on individual projects. The calculators state their assumptions and name the standards they follow so you can take that to someone qualified to sign it off. Anything with real consequences — structural, electrical, medical, or financial — needs a professional who can take responsibility for the answer, which a website cannot do.
Response times
This is a side project rather than a company, so replies come in evenings and at weekends. Expect a few days; corrections tend to be quicker than requests because they are usually a smaller decision. If something is badly wrong on a page, say so plainly in the subject line and it will get looked at sooner.
Privacy
Your email address is used only to reply to you. It is not added to any list, and there is no newsletter to be added to. Nothing you type into a calculator is ever transmitted anywhere — see theprivacy policy for the details.