Formula selection
Each calculator identifies its formula or estimation method and defines the required inputs, units and validation limits. Where a result depends on assumptions, those assumptions are shown near the tool.
Testing and review
Default scenarios and edge cases are tested against independent calculations. Date, domain and divide-by-zero checks prevent misleading output. Material changes should receive an updated review date and, for high-impact topics, an appropriately qualified reviewer.
Limitations
Browser calculations are educational estimates. Live market data, local regulations and personal circumstances may require a specialist source. We welcome reproducible correction requests through the contact page.