About CompoundPage
145 free calculators that show their method and name their sources.
What CompoundPage is
CompoundPage publishes free calculators in 9 categories: math calculators; geometry calculators; chemistry calculators, physics and lab tools; conversion calculators; date and time calculators; business calculators; random generators; everyday cost calculators; and free online tools. Each one explains how it works, and any figure that is not plain arithmetic names the source it came from.
How the numbers are checked
Arithmetic, such as a mortgage payment, a unit conversion or a quadratic root, is covered by automated tests, and the site is not published if any of them fail.
Published figures, such as tax brackets, inflation indices and material densities, come from a named source. A calculator that relies on a figure not yet checked against that source, or one due to be checked again, is withheld until it has been.
Calculators where an error could be costly, in areas such as tax, payroll, lending, health and construction, are published only after a qualified person has reviewed the method. The reviewer's name and credential appear under the calculator's heading.
Tests and reviews reduce errors; they do not eliminate them, and no result is guaranteed to be correct.
What CompoundPage is not
It is not advice. The calculators are general-purpose tools that compute what you ask them to compute. A tax, payroll, lending, medical or structural decision depends on facts no calculator knows about you, and a result here is an estimate to take to somebody qualified, not a substitute for asking them. Use of CompoundPage is subject to the Terms of Use.