Contact
Corrections, questions and useful feedback.
If a formula is unclear, a published assumption is wrong or a link no longer works, send the page address and a short explanation.
What not to send
Do not send passwords, payment-card numbers, identity documents or private customer data. Calculator inputs can be described in general terms without sharing personal records.
Response expectations
This is a small independent project. Messages about factual corrections, accessibility problems and broken links are prioritized. Commercial partnership messages should identify the company and the proposed relationship.