How we build our calculators

Every calculator on this site is built against the standard, published formula for its category — amortization formulas for loans, WHO thresholds for BMI, credit-weighted averages for GPA, and so on. Each calculator page shows that formula, plus a step-by-step breakdown and a worked example, so the math is never hidden.

Results are estimates for informational purposes. For decisions with legal, medical, or financial consequences, confirm with a qualified professional.