Fidamen

Boat Loan Balloon Payment Calculator with Bi-Weekly Payments

This calculator estimates periodic payments for a boat loan that includes a balloon payment at the end of the loan term. It supports bi-weekly payments (26/year) by default and also allows other frequencies. Use the two modes to either compute the periodic payment for a given balloon or compute the balloon required for a desired periodic payment.

The tool provides totals and estimated interest to help you compare alternatives and plan refinancing or payoff strategies. Results are mathematical estimates and do not replace lender quotes or signed loan documents.

Updated Nov 2, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 0e9bec93af97 • Reviewed by Fidamen Standards Committee

Calculate the level periodic payment (bi-weekly by default) that amortizes the loan to a specified remaining balloon (future value) at the end of the term.

Inputs

Results

Updates as you type

Periodic payment

$0.77

Balloon amount at term end

$10,000.00

Total paid (payments + balloon)

$10,100.26

Total interest paid

-$39,899.74

Number of payments

130

OutputValueUnit
Periodic payment$0.77USD
Balloon amount at term end$10,000.00USD
Total paid (payments + balloon)$10,100.26USD
Total interest paid-$39,899.74USD
Number of payments130—
Primary result$0.77

Visualization

Methodology

Calculations use standard loan mathematics for level (constant) periodic payments with a specified future value (balloon). The formulas derive from time-value-of-money relationships for annuities and future values.

We follow safe numeric practices for financial calculations, including using periodic interest rates (APR divided by payments per year) and counting the total number of periodic payments as term years times payments per year. Rounding follows IEEE floating-point convention; implementation should use a stable numeric library and validate results against known examples during QA consistent with ISO 9001 processes. For integrity and reproducibility, follow NIST guidelines for computational reproducibility and IEEE 754 for numeric behavior.

Worked examples

Example 1: $50,000 loan, 6.5% APR, 5 years, bi-weekly (26). With a 20% balloon ($10,000), the calculator returns the bi-weekly payment and totals.

Example 2: Same loan and term but you want to limit bi-weekly payments to $300; use the 'compute balloon from payment' mode to see the balloon required to achieve that payment.

F.A.Q.

Does this calculator include fees, taxes, or insurance?

No. This tool calculates interest and payments based on principal, APR, term, and balloon. Add any fees, taxes, or insurance to the financed amount before using the calculator if you want them included.

Why might the lender's quote differ from this calculator?

Lenders may use different APR definitions, include fees rolled into finance charges, use daily-interest accrual, or round payments differently. Always compare to the lender's amortization schedule and disclosure documents.

Why is bi-weekly shown as 26 payments per year?

Bi-weekly payments are every two weeks, typically resulting in 26 payments per calendar year. Some lenders use semi-monthly schedules (24 payments); choose the frequency that matches your loan contract.

How accurate are the results?

Results are mathematically accurate to standard floating-point precision, but are estimates. For regulatory or contract decisions, rely on lender-provided disclosures. See accuracy notes and citations for recommended numeric and QA standards.

Sources & citations

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: 0e9bec93af97

What changed (latest)

v1.0.0 • 2025-11-02 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 2, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-02 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: df44c65fd8e8