Sources & References

Our calculators use established financial mathematics: the standard amortization formula for fixed-rate loans, the compound-interest formula for growth and savings, present- and future-value equations for retirement, and standard payroll withholding conventions for income calculators. These are the same equations used across the finance industry and in standard finance textbooks.

Where a calculator or guide relies on a specific reference, rate convention, or regulatory standard, that source is cited on the page itself. We prioritize widely-accepted, peer-reviewed financial principles and official publications over secondary sources.

Default values (such as a typical compounding frequency or a generic tax assumption) are chosen to be reasonable for a general audience and are always stated on the relevant calculator page. They are not personalized advice. See our methodology for how we choose and document assumptions.

Results are estimates based on the inputs you provide and the assumptions shown. We review sources and methodology as standards evolve. If you believe a reference is outdated or a calculation could be improved, please contact us.