Get in touch
Contact
Questions about a result, a formula that looks off, or a tool you'd like to see — email is the way. I read everything and reply to most within a couple of days.
ianwelkins@gmail.com — maintained by Ian Welkins.
For the fastest handling, put the page name in the subject line and, for a calculator question, include the numbers you typed. Screenshots of the console help more than descriptions of it.
Report an error
Found a wrong number, a broken table or a formula that doesn't match the Methodology page? That's the most valuable email this site gets. Tell me the page, the inputs you used and what you expected, via the dedicated report an error page — corrections are verified, fixed and credited there.