Where every number comes from

Source hierarchy, in the open

We prefer the agency or dataset publisher: IRS guidance for federal tax figures; SSA for the wage base and actuarial life tables; the Federal Reserve Survey of Consumer Finances for net-worth percentiles; Census ACS; and the World Bank.

State tax estimates need extra care because agencies publish on different calendars. The state dataset starts with the Tax Foundation's 2026 compilation, then records enacted changes and available state-agency material. If a state's 2026 inflation-adjusted liability thresholds were not published at review time, the page says which earlier official thresholds are being used as an estimate. Every state page links the source material it relies on and distinguishes annual liability estimates from payroll withholding.

A source link does not make an estimate exact. Each data-backed page should also state its vintage, exclusions, and the point at which professional verification is appropriate.

Vintages are visible

Data ages. Where a calculator depends on survey or snapshot data, the page shows the vintage right next to the result — "Federal Reserve SCF 2022," "Census ACS 2023," "SSA 2021 life table" — instead of implying the numbers are live. Currency rates state their snapshot date and that they are not live quotes.

When the honest number is unpopular, it stays

When Congress repealed the federal EV and residential-energy credits in 2025, our defaults moved to $0 and the payback periods got longer — solar's honest default payback went from 9.8 to 13.2 years. Calculators that sell things keep the pretty version; we don't sell things, so we don't have to.

Verified by repeatable checks

Engines use canonical test vectors—known inputs with expected outputs—and the site has automated browser checks for rendered results. Those checks lower the chance of regressions; they do not turn an estimate into professional advice. For taxes, investments, health, legal matters, or any consequential decision, verify the assumptions and seek qualified advice where appropriate.

Nothing steers the answer

No ads, no affiliate placements, no lead forms, no accounts. All math runs in your browser; inputs are never transmitted. Measurement is limited to cookieless aggregate page counts and a small allowlisted set of anonymous product outcomes described on the about page. There is no revenue model attached to what result you get.

Update cadence & corrections

Tax-year figures are refreshed when the IRS publishes them (typically October–November for the following year). Legislative changes are folded in with the page noting the change, as with the 2025 credit repeals. Found an error? Tell us via the contact on the about page — corrections ship with the same test-vector treatment as everything else.

Reference pages

The datasets behind the calculators, published as citable pages: the IRS Uniform Lifetime Table and the 2026 IRS numbers. All of them are listed on the reference tables page.