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Finance & LoansGenerated accuracy model review: 2026-05-06
Boat Loan Calculator accuracy and testing
This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.
Formula source
- The calculator uses the standard amortization formula found in mortgage and auto loans: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]. Marine loans simply tend to have higher interest rates and longer 'n' (terms) than auto loans.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Boat Price: $50,000
- Down Payment: $10,000
- Interest Rate: 7.5%
- Loan Term: 15 Years
Expected outputs
- Estimated Monthly Payment: $370.80
- Total Interest Paid: $26,744.89
- Total Loan Cost: $76,744.89
Known limitations
- Does not include sales tax, registration, or ongoing slip/storage fees.
Assumptions
- Inputs are interpreted exactly as entered in the calculator form.
- The calculation runs locally in the browser using the current checked-in calculator definition.
Unit handling
- Boat Price accepts values in $.
- Down Payment accepts values in $.
- Interest Rate accepts values in %.
- Loan Term accepts values in Years.
- Estimated Monthly Payment is displayed as currency.
- Total Interest Paid is displayed as currency.
- Total Loan Cost is displayed as currency.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
- Currency outputs are displayed with standard US dollar formatting.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current boat-loan-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for Boat Loan Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.