Contact
Corrections come first
If a figure on this site is wrong, that is the most important message it can receive. A calculator that is wrong is worse than one that does not exist, and the failure is silent — nobody files a bug against a number, they close the tab. Include the page and the figure you think is off, and where you think the right one comes from if you know.
Everything else
Questions about how something is calculated, requests for a calculator that does not exist yet, and anything about privacy or advertising go to the same address.
What this address is not
It is not a route to financial advice, and a reply will not contain any. BriskCal shows arithmetic and cites its sources; recommending a course of action is a regulated activity and not something a calculator does. For advice about your own circumstances, the Financial Conduct Authority keeps a register of authorised firms at register.fca.org.uk, and MoneyHelper is the government-backed free guidance service.