Fidamen

Boat Loan Refinance Calculator with Bi-Weekly Payments

This calculator helps owners compare an existing boat loan to a refinance offer and model the effect of switching to bi‑weekly payments. It reports periodic payments, total interest, annual cashflow differences, and an estimated break‑even time for closing costs.

Use conservative inputs: if you plan to finance closing costs, include them in the refinance amount. Results are estimates for planning purposes and assume fixed rates and timely payments.

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

Governance

Record 3055ae4bfe82 • Reviewed by Fidamen Standards Committee

Compares your existing loan obligations to a proposed refinance loan. Calculates periodic payments, total interest remaining, annual cashflow, estimated annual savings, and break‑even years for closing costs.

Inputs

Results

Updates as you type

Current payment (per period)

$579.98

Current total interest remaining

$4,799.04

Refinance payment (per period)

$261.04

Refinance total interest (life of new loan)

$3,934.77

Amount financed (principal + closing costs)

$30,000.00

Estimated annual savings (cashflow)

$172.85

Break‑even (years to recover closing costs)

0

OutputValueUnit
Current payment (per period)$579.98USD
Current total interest remaining$4,799.04USD
Refinance payment (per period)$261.04USD
Refinance total interest (life of new loan)$3,934.77USD
Amount financed (principal + closing costs)$30,000.00USD
Estimated annual savings (cashflow)$172.85USD
Break‑even (years to recover closing costs)0years
Primary result$579.98

Visualization

Methodology

Calculations use standard amortization formulas. Periodic interest rate = APR / periods_per_year. Payment per period is calculated with the canonical annuity payment formula: payment = r*PV / (1 - (1+r)^-n). Total interest = sum(payments) - principal.

Bi‑weekly effects are estimated by treating a bi‑weekly schedule as 26 equal payments per year and applying the periodic amortization formula at the bi‑weekly period rate. This captures both the effect of smaller, more frequent payments and the extra annual principal paid compared to 12 monthly payments.

Key takeaways

Be explicit about what you include in the refinance amount (principal only vs principal + closing costs).

Switching to a bi‑weekly schedule can reduce interest and shorten term, but the exact benefit depends on whether your lender applies payments immediately and whether you make 26 payments a year.

Worked examples

Example: $30,000 current balance, 6% APR, 60 months remaining, refinance to 5% APR for 5 years with $500 closing costs. The calculator shows new payment, total interest, annual savings and break‑even time.

Bi‑weekly example: If your monthly payment is $575, making bi‑weekly payments of $287.50 yields 26 payments/year (equivalent to 13 monthly payments) and typically shortens the loan and reduces total interest compared with 12 monthly payments.

F.A.Q.

Does this calculator include taxes, insurance, or variable interest rates?

No. This tool models fixed interest, principal and interest amortization only. Taxes, insurance, and variable rates are excluded and must be considered separately.

What does 'bi‑weekly' mean here?

Bi‑weekly in this model equals 26 payments per year (every two weeks). Some lenders call accelerated monthly plans 'bi‑weekly' but apply payments differently; results assume true 26 payments per year.

How should I treat closing costs?

If closing costs will be added to the new loan, enter them in the closing costs field. If you pay them upfront, set closing costs to zero and consider them separately when evaluating break‑even time.

How accurate are the estimates?

Estimates use standard amortization math but are approximate. Minor differences can occur due to rounding, lender timing rules, daily interest accrual methods, or fees not modeled here.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: 3055ae4bfe82

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: eeeea20c9449