How our calculators work
We aim to make every result traceable to a visible formula and understandable assumptions.
1. Start with a standard formula
Each calculator is based on a commonly used mathematical or business formula. We express that formula in plain language and keep units consistent.
2. Make assumptions visible
Where a calculation depends on timing, rates, compounding, rounding, or other assumptions, those assumptions should be stated on the calculator page.
3. Test common and edge cases
We check expected scenarios as well as zero values, invalid denominators, negative results where meaningful, and rounding behavior.
4. Keep estimates separate from advice
A correct formula can still be inappropriate for a particular legal, tax, accounting, lending, investment, or regulatory situation. Results are therefore presented as informational estimates.
5. Update when formulas or requirements change
General math rarely changes, but external rules can. Calculators tied to jurisdiction-specific rules should include a verification date and source before being published as rule-specific tools.