About DueMATH
What DueMATH is
DueMATH is a small set of free calculators for a handful of financial questions that are easy to get wrong and expensive to guess at: inheritance tax, federal and state estate tax, 401(k) rollovers, student loan refinancing, and gig-worker quarterly taxes. Each calculator shows its sources and its methodology alongside the number, not just the number — see the Methodology page for exactly what that means calculator by calculator.
Who builds it
DueMATH is built and maintained by an independent developer, not a financial institution, a CPA firm, or a large media company. That's worth knowing plainly rather than implying otherwise: no calculator on this site has been reviewed by a licensed CPA or tax attorney. What DueMATH does instead is disclose, calculator by calculator, exactly which state or federal source each figure was checked against and when — so you can judge the number on its sourcing rather than on a brand name.
How it stays current
Tax rules change — brackets shift, exemptions get indexed, states repeal or introduce taxes. Every calculator page shows its own last-verified date, and the Methodology page explains how that date is computed and what a “verified against primary source” versus “approximation” label actually means.
Get in touch
Found a number that looks wrong, a state that changed its rules, or something on the site that's just broken? See the Contact page.