Transparent models, visible limits.

How estimates are built

Calculation functions are kept separate from the interface and tested with representative cases, boundaries, zero values, and invalid inputs. Currency is calculated at full precision and rounded only for display. Defaults are editable examples, not recommendations.

What a source means here

Primary government and public-agency sources support definitions, standard formulas, and decision factors. Some tools—especially home affordability, car affordability, investment growth, emergency funds, and rent versus buy—combine those concepts in a disclosed TrueCost planning model. A citation does not mean the publisher reviewed or endorses TrueCost.

Review and correction process

Each calculator shows its most recent substantive review date. A review checks formula behavior, explanatory copy, source links, and known model limitations. A date is changed only after that review is completed.

Found a problem? Send the calculator name, the inputs you used, and the result you expected. Do not include account numbers or other sensitive data.

Calculator source index