Methodology & Sources

We believe a calculator is only useful if you can trust the number it returns. This page explains how CalcWisee builds, tests, and documents its tools.

How we build calculators

Each calculator implements a documented, industry-standard formula. Financial tools use standard amortization and compound-interest mathematics; health tools follow recognised clinical formulas; conversion tools use exact, internationally defined conversion factors.

Sources & references

• Finance: Standard amortization, present/future value, and APY formulas as taught in financial mathematics.
• Health: BMI (WHO classification), Mifflin-St Jeor equation for BMR/TDEE, and Naegele’s rule for due dates.
• Math & conversions: Standard arithmetic identities and SI/international conversion factors.

Testing & updates

Results are checked against known reference values. Calculators show a last-updated date, and we revise them when standards change or issues are reported.

Spotted a discrepancy? Let us know and we’ll review it.