Fidamen

Boat Loan APR Calculator with Bi-Weekly Payments

This calculator estimates periodic loan payments and key totals for a boat loan when you choose bi‑weekly payments (26 payments per year) or another payment frequency. Enter the loan amount, APR, term, any upfront fees, and optional extra payments per period to see payment, total cost, and effective annual rate.

Results use the standard fixed‑rate loan annuity formula and show both the payment per period and a monthly equivalent for comparison. Use the payments per year field to switch between bi‑weekly (26) and monthly (12) schedules.

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

Governance

Record ad141b0e6316 • Reviewed by Fidamen Standards Committee

Inputs

Results

Updates as you type

Payment per period

-$0.29

Total amount paid (principal + interest + fees + extra payments)

-$75.00

Total interest paid

-$30,075.00

Effective annual rate (compounded by payment frequency)

240000.00%

Equivalent monthly payment (for comparison)

-$1.35

OutputValueUnit
Payment per period-$0.29—
Total amount paid (principal + interest + fees + extra payments)-$75.00—
Total interest paid-$30,075.00—
Effective annual rate (compounded by payment frequency)240000.00%—
Equivalent monthly payment (for comparison)-$1.35—
Primary result-$0.29

Visualization

Methodology

The payment formula assumes a fixed nominal APR applied to each compounding period. Periodic rate r = APR / payments_per_year. Number of periods n = term_years × payments_per_year. Periodic payment for an amortizing loan: Pmt = principal × r / (1 − (1 + r)^−n).

Upfront finance fees are added to the borrower cost shown in total paid but are not used to modify the nominal APR in this simple tool. Computing an APR that legally includes fees requires an internal rate of return (IRR) or iterative calculation and may be subject to local disclosure rules.

Key takeaways

Use payments_per_year = 26 for bi‑weekly comparisons. This calculator uses the standard amortizing loan formula and reports periodic payments, total cost, and effective annual rate for frequency comparisons.

For legally required APR disclosures or contract reconciliation, validate results against lender disclosures and consider an IRR/iterative APR calculator that includes fees.

F.A.Q.

Does this calculator compute legal APR including fees?

No. This tool treats fees as an additive cost shown under total paid. Legal APR that incorporates fees requires an IRR/iterative calculation and may vary by jurisdiction. Consult your lender's APR disclosure or use a tool specifically labeled 'APR including fees' for legal comparisons.

Why are bi‑weekly payments sometimes shown as savings versus monthly?

With more frequent payments (26 vs 12), interest compounds on a smaller outstanding balance between payments, which can reduce total interest over the same nominal APR. This calculator shows the effective annual rate (EAR) for frequency comparison.

How accurate are the results?

Results are accurate to the level of the underlying mathematical model (standard amortizing loan formula). They do not account for lender rounding rules, payment schedule alignment, daily interest conventions, or taxes and insurance. For contract‑level accuracy, review your loan agreement and lender disclosures.

Can I use this for irregular payment schedules?

This tool assumes fixed, regular periodic payments. Irregular schedules, balloon payments, or interest‑only periods require a schedule builder or loan amortization tool that supports those features.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: ad141b0e6316

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: 10f2896b2539