Chris Terry owns this site's accuracy. He built the three calculators and signs off on any change to a formula or a published figure. Priya Raman writes the guides; see the authors page for both.
Where the figures originate
The federal exemption ($15,000,000 for 2026) and the 40% top rate come from IRS Rev. Proc. 2025-32. State figures are pulled from each state's own revenue department or its enabling statute; the state dataset page lists a source and a verification flag for every one of the thirteen jurisdictions individually, rather than treating them as a single block. Some states (Illinois, Maryland, Massachusetts, Minnesota, Oregon, Vermont) use flat statutory thresholds that don't move year to year. Others, like New York and Rhode Island, adjust annually and get rechecked against the state's own published table each time.
How the calculators get tested
Each calculator runs a published formula, not a black box: the federal exemption and marital deduction rules for the main estate tax tool, the $19,000 annual exclusion and lifetime exemption tracking for the gift tax tool, and date-of-death basis reset for the step-up tool. Before a formula ships or changes, it's run against known scenarios (a zero-tax estate, an estate that clears the federal line, an estate that owes only at the state level) and checked by hand against the expected result.
What we do when something's wrong
If a figure doesn't match its cited source, or a calculator produces an unexpected result, tell us the page and the discrepancy. Priya checks content and state figures; Chris checks anything involving a formula. Corrections that involve a real error usually go live within a few days, and the CSV dataset's "last verified" date updates accordingly.
Independence
A small number of footer links across this site are affiliate links to other tools in the Encore Editorial network. That relationship has no bearing on which state's exemption we report or how a calculator computes its result. If we ever get that wrong, the correction process above applies to us the same as anyone.