Contact

Suggestions, corrections, and collaboration are all welcome.

Email me directly — I read every message myself.

• Something is wrong — tell me which article and which part, and I'll check it, fix it, and note the revision date.
• A calculator looks off — send the values you entered and I'll reproduce it.
• I'd like a calculator for… — suggestions welcome; several of the existing ones started this way.
• Partnership or advertising — same address.

Jay · replies usually take two or three days.