Talk to a real person
Whether you have spotted a wrong number, want a calculator that does not exist yet, or would like to work together, your message comes straight to the small team that builds the site. No ticket queue, no bots.
✉What can we help with?
Report a wrong result
Think a number is off? This is the message we most want to receive. Tell us the tool and your inputs and we will investigate quickly.
Suggest a calculator
Need a tool we do not have yet? Describe what it should do and who it is for — many of our tools started as a single request.
Report a bug
Something broken, misaligned or behaving oddly on your device? Let us know the page and your browser so we can reproduce it.
Business & press
Partnerships, licensing, or a press question? Use the same address and mark it for business, and we will route it to the right person.
iWhat to include
A little detail helps us help you faster. If you are reporting a result you think is wrong or a bug, it is ideal if you can include:
- Which calculator you were using (the page name or link).
- The exact inputs you entered, including the units.
- What you got and what you expected, and if possible where your expected figure comes from.
- Your device and browser for display or behaviour issues (for example, "iPhone, Safari" or "Windows, Chrome").
None of this is required — a quick note is always welcome — but the more you can share, the faster we can pin down and fix the problem.
?Common questions
How quickly will I hear back?
We are a small team, so we usually reply within two to three working days. Reports of a wrong result tend to jump the queue, because getting the numbers right matters most to us.
I think a calculator is giving the wrong answer. What should I do?
Please email us with the tool, your exact inputs and units, the result you got and the result you expected. We will re-check the formula against our sources and, if there is a genuine error, prioritise a fix — usually within days. You can read how we verify and correct tools on our methodology page.
Can you build a custom or private calculator?
Possibly — send us a description of what you need and how you would use it. Mark the message for business and we will tell you whether it is something we can help with.
Do you offer personal financial, medical, legal or engineering advice?
No. Our calculators are educational tools that provide estimates, and we cannot give personal professional advice. For decisions with real stakes, please consult a suitably qualified professional. Our disclaimer explains this in full.
Prefer to just explore?
Head back to the library and find the tool you need — no message required.