One address, read by the person who maintains the site.
This is the one we want most. A calculator that gives a confidently wrong answer is the worst thing this site can do, and a report gets acted on ahead of anything else on the list.
To make it quick to reproduce, include:
All 48 tools in the catalogue are built, so a suggestion now means adding something new rather than moving it up a queue. It is still worth sending — a request is evidence, and evidence is what decides whether something gets built at all. Say what you were trying to work out and what you had to use instead.
Questions about the privacy policy, or a request about personal data, go to the same address. Note that calculator inputs never reach us, so there is nothing held about you from using the tools.
It is not a helpdesk for your payslip, your loan application or your tax filing. We cannot see your records, we are not your employer, your bank or the BIR, and nothing sent here is professional advice. For anything specific to your own case, ask someone qualified — the disclaimer explains why.