Methodology
How our calculators are built
utility.finance calculators are educational models. Each tool starts with standard financial math, names the assumptions that drive the result, and shows where a simplified calculator can differ from a lender quote, account statement, or full financial plan.
Formula sources and implementation
Mortgage and refinance tools use amortization formulas based on loan balance, rate, term, and payment timing. Savings and compound-growth tools use future value calculations with contribution assumptions. Debt tools model balance, APR, minimum payment, and extra-payment order.
When a calculator requires a judgment call, such as how to treat maintenance, opportunity cost, or irregular payment behavior, the page explains the assumption in plain English rather than hiding it in the result.
Assumptions and limits
Inputs entered by users are treated as scenario assumptions. The calculators do not verify credit, underwriting rules, lender fees, local taxes, insurance prices, market returns, or personal eligibility.
Results are estimates for comparison and planning. They can help you see direction, magnitude, break-even timing, and sensitivity, but they are not guarantees.
Review process
We review calculator pages when formulas change, when examples are expanded, when a reader reports an issue, or when supporting content reveals that an assumption should be clearer.
Review includes checking the visible result labels, calculator inputs, examples, related guides, and disclaimer language so users can understand both the result and its limits.
Corrections
If you believe a formula, explanation, example, or link is wrong, send the page URL and a short description to utilityfinance.support@digitalrichkid.com.
Substantive corrections may update the page wording, result explanation, linked guide, or visible last-updated date.
Related policies
Last updated May 17, 2026