Send a message to [email protected] using the form below or your email app. We use your reply address and message to handle your request.
For a suspected error, include the tool URL, reproducible non-sensitive sample inputs, expected result, actual result and a supporting source. Do not send salary records, passwords, personal documents or account credentials.
Each tool lists its method, assumptions and sources. The contact form sends only the information you type into it; it does not attach calculator inputs or files.