What the site publishes
Each calculator starts with a concrete question: How quickly did an investment grow? How much might inflation change a future cost? Would a balance transfer save money? How much mortgage interest could an extra payment avoid?
The current tools cover investment growth, inflation, investment fees, savings goals, debt and liquidity, balance-transfer offers, and mortgage payoff planning. Companion guides explain the assumptions, realistic examples, and situations that simplified calculations do not model.
How calculators are developed
Calculator logic is checked against known examples,
independent calculations, boundary values, and invalid
inputs before publication. Testing also looks for broken
keyboard navigation, JavaScript errors, and unexpected
results such as NaN or
Infinity.
Results are rounded for readability while the underlying calculation generally keeps more precision. Twelve decimal places can still produce the wrong decision when the input assumption is wrong, so each page explains the assumptions that matter.
The Calculator Methodology describes shared calculation methods, rounding, payoff timing, and common exclusions.
Sources and explanations
Guides favor primary and authoritative sources when practical, including government agencies, regulators, official program documentation, and institutions responsible for the relevant rules.
Public explanations aim to solve a specific problem with plain language, concrete examples, and enough detail to show where the answer came from. A polished sentence cannot rescue a missing assumption.
Calculator entries and analytics
Calculator entries are processed in the visitor's browser. Sunset Guardian's custom calculator events record only that a calculator was used or that a related guide was opened, along with a fixed calculator name.
Those events do not include balances, rates, payments, income, savings, calculator results, or free-text values. The Privacy Policy explains the site's broader analytics and privacy practices.
Limitations and corrections
The calculators provide educational estimates. Actual statements and outcomes may differ because of taxes, fees, posting dates, daily-interest methods, changing rates, account rules, contract terms, or circumstances the tool does not ask about.
When a material issue is found, the calculation, explanation, or companion guide should be corrected rather than hidden behind a new example. Financial agreements, official statements, and applicable rules control the real transaction.
Use the tools to compare scenarios and identify the assumption that changes the decision. Confirm that assumption before committing money.