About RuleCost
Calculators that turn one specific rule change into a dollar amount — built from primary sources, reviewed before publishing, and updated when the rules are.
Updated 17 Sept 2026
Tax law changes. Subsidy rules change. Benefit thresholds move every year. Almost every time, the actual effect — the number that lands in your bank account or your tax bill — is buried in a government publication, a Revenue Procedure, or a regulation nobody reads for fun.
RuleCost exists to close that gap. Each calculator on this site covers exactly one rule change and answers exactly one question: given your numbers, what does this actually cost or save you?
What we do
- Pick a rule that moves real money for a meaningful number of people — not obscure edge cases.
- Build a calculator around it, using the plain text of the law or regulation, not a summary of a summary.
- Show the assumptions and the math openly, so the result isn’t a black box.
- Cite the primary source for every figure, with the date it was last checked.
- Update the numbers when the rule does — a page here never quietly goes stale.
Every calculator is published under the RuleCost Editorial Team byline — see that page for what “reviewed by” actually means here.
What we don’t do
RuleCost is not a financial advisor, a tax preparer, or a law firm. Nothing on this site is personalized advice — see the disclaimer for the specifics. We also don’t sell your data, because there isn’t any to sell: every calculator runs in your browser, and your inputs are never sent to our servers.
How this is funded
RuleCost is free to use and funded by display advertising. Ads never influence which rules we cover or what a calculator’s result says — see the editorial policy for how that separation works in practice.
Questions, corrections, or a rule you think we should cover next? Get in touch.