Calculation Methodology

Calculation methodology is the documented process used to turn inputs into reproducible results. CalcPilot publishes the applicable formulas, unit definitions, assumptions, rounding rules, and limitations below so each estimate can be independently checked.

How calculations are produced

Every calculator runs locally in your browser. Inputs are passed to deterministic TypeScript functions, so the same values and settings produce the same result. Displayed figures are rounded for readability; calculations use the full JavaScript number precision until the final formatting step.

Loan and mortgage payments

Fixed-rate payments use the standard amortization formula: payment = principal × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where r is the periodic interest rate and n is the number of payments. Taxes, insurance, fees, and extra payments are displayed separately when a tool includes them. Apply this formula with the Mortgage Calculator or the Loan Calculator.

Savings and compound interest

Growth projections compound the starting balance at the selected frequency and add regular contributions over the selected period. Rates are user-provided assumptions, not live quotes or forecasts. Actual returns, taxes, fees, and inflation can materially change the outcome. Model regular deposits with the Savings Calculator, or isolate compounding with the Compound Interest Calculator.

Salary estimates

Salary results convert annual gross pay into monthly, weekly, and hourly equivalents. The tax field is an effective-rate assumption supplied by the user; CalcPilot does not calculate jurisdiction-specific payroll taxes or replace an official payroll estimate.

Unit conversions

Each converter publishes its factor or formula beside the result. Ratio conversions multiply or divide by a fixed factor. Temperature conversions also apply the required offset. The data converter explicitly uses binary units, where 1 GB equals 1,024 MB. For example, the kg to lbs converter applies the published weight conversion factor in either direction. The currency converter loads a public ECB reference rate via Frankfurter (with an open CDN fallback) and still lets you override the rate manually.

Health estimates

BMI uses weight divided by height squared and reports the adult screening categories published by the US Centers for Disease Control and Prevention. BMR uses the Mifflin–St Jeor equations described in the original peer-reviewed study, then applies a user-selected activity multiplier to estimate daily energy needs. These are screening and planning estimates, not diagnoses or individualized medical advice.

Reference standards

Unit definitions are checked against the National Institute of Standards and Technology SI guidance. Mortgage terminology and consumer-facing assumptions are cross-checked against the Consumer Financial Protection Bureau. Currency pages identify the timestamp and source of each reference rate; a displayed rate is informational and may differ from a bank, card network, or money-transfer quote.

Verification and corrections

Worked examples, boundary cases, and inverse conversions are checked during development. The source code is public, so formulas can be independently reviewed. If a result looks wrong, include the calculator name, inputs, expected result, and a reliable reference in a GitHub issue.

Last reviewed: August 26, 2026. Results are estimates for planning and educational use only. See the Disclaimer before making financial, legal, tax, health, or other consequential decisions.