Contact
Email is the only channel right now — no live chat, no phone line, no contact form that goes into a queue nobody reads. Write to:
What's useful to include
If you're flagging a number that looks wrong, name the specific calculator and state (for example, “Pennsylvania inheritance tax calculator”) and what you'd expect instead — that's usually enough to check it against the source and fix it if it's actually off. There's no guaranteed response time; this is a small, independently run site, not a support desk.
Not for
DueMATH doesn't provide personalized tax, legal, or financial advice by email or otherwise — see the Terms of Use. For anything specific to your own situation, a licensed CPA, tax attorney, or your state's Department of Revenue is the right place to ask.