Email the developer
Send questions or feedback to [email protected]. This is the public contact for the website, including privacy and terms inquiries. There is no on-site contact form.
Reporting a calculation issue
Include the page URL, the inputs and selected units, the result shown, and the answer you expected. A short, reproducible example and a relevant source help identify the issue.
Do not send account passwords, payment details, confidential customer records or sensitive shipment information. Screenshots should be redacted before you send them.
What to expect
Messages are handled by an individual developer. No response-time or round-the-clock support commitment is offered. For shipment bookings, invoices or carrier decisions, contact the relevant provider directly.