How our calculators work

Every calculator on this site is built from two parts: a rule pack and an engine. A rule pack is a data file that holds the numbers a state's law sets, such as guideline percentages, income caps, and interest rates. Each number in a pack carries a citation to an official source, usually the statute or the state agency that publishes it, plus the date we last reviewed it.

The engine is the part that does the math. It reads your inputs and the rule pack, then applies the state formula step by step. Nothing is hidden: the result shows each line of the calculation, and each line links to the source it comes from. If an input falls outside what the formula covers, the tool says so instead of guessing.

Before a state calculator goes live, we write test scenarios by hand from the statute. Each scenario works the formula out on paper, records every step, and states the expected result. The Texas pack ships with 10 such scenarios. Five of them were also entered into the official Texas OAG monthly child support calculator on August 6, 2026, and matched to the cent. The other five are hand-computed and marked as pending an official cross-check. Our test suite runs all of these scenarios against the engines on every change.

The state map and table cover all 50 states and DC, but only 51 states have a completed, source-backed research pack today. For the rest, we show the guideline model classification with its source and mark the state as in progress. Where a state formula needs inputs our standardized example does not define, the table says "See state page" with the reason, because we do not publish invented figures.

Every result carries the same disclaimer stack: these are estimates, the court or state agency calculation controls, this site does not give legal advice, and it is not affiliated with any government agency. Guideline support is also only part of most orders; judges can and do deviate.

If you find a number that does not match an official source, please contact us. Dated corrections and rule changes are listed on the updates page.