Fidamen

RV Loan Payment Calculator with Extra Payments

This RV loan calculator estimates scheduled payments, the impact of recurring extra payments and/or a single one-time extra principal payment on payoff time and interest paid. Use it to compare the 'no extra' case to adding extra principal each period or a one-time lump-sum payment.

Results are estimates based on standard amortization math and assume fixed interest rate, equal payment periods and that extra amounts are applied directly to principal. See methodology and accuracy notes below.

Updated Nov 17, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 7c6b99d7a1f7 • Reviewed by Fidamen Standards Committee

Estimates effect of recurring extra principal payments and a single one-time extra principal payment applied at a chosen payment number. Returns adjusted payoff time, total interest and interest saved compared to standard amortization.

Inputs

Advanced inputs

Recurring extra payment

Recurring extra payment (when both selected)

One-time extra payment

One-time extra payment (when both selected)

Results

Updates as you type

Scheduled payment per period (no extra)

$435.55

Payment per period including recurring extra

$435.55

Estimated number of payments until payoff

—

Estimated payoff time (years)

—

Estimated total interest (with extra payments)

—

Estimated interest saved vs no extra

—

OutputValueUnit
Scheduled payment per period (no extra)$435.55USD
Payment per period including recurring extra$435.55USD
Estimated number of payments until payoff—payments
Estimated payoff time (years)—years
Estimated total interest (with extra payments)—USD
Estimated interest saved vs no extra—USD
Primary result$435.55

Visualization

Methodology

Calculations use a periodic-rate amortization model: periodic rate = APR / payments per year. The scheduled payment is computed from the closed-form amortization formula. When a one-time extra is specified, the tool computes the remaining balance immediately before that payment, subtracts the extra amount, then recomputes remaining payments assuming the same per-period payment plus any recurring extra.

For recurring extra payments the tool treats the combined per-period payment (scheduled payment + recurring extra) as the new per-period payment and computes the number of periods until payoff using the logarithmic closed-form solution. Interest saved is the difference between total interest in the baseline schedule and the adjusted schedule.

Worked examples

Example 1: $50,000 principal, 6.5% APR, 15 years, monthly payments. Adding $100 recurring to each payment reduces payoff time and total interest; the tool shows estimated years saved and interest saved.

Example 2: Same loan but applying a one-time $5,000 principal payment at payment 12 reduces the remaining balance immediately; the tool recomputes remaining number of payments and updated interest.

F.A.Q.

Does this calculator account for fees, insurance or taxes?

No. This tool models principal and interest only. Fees, taxes, insurance and other escrow items are excluded unless entered as part of the loan amount.

Are results exact for every schedule?

Results are mathematically consistent with standard amortization formulas for fixed-rate loans and the assumptions stated. However, small differences can occur versus lender statements due to rounding conventions, daily interest accrual, payment timing variations, or different application order for extra payments.

Can I use this with biweekly or weekly payments?

Yes. Choose the payment frequency (monthly, biweekly, weekly). The tool converts APR to the corresponding periodic rate and applies the same formulas.

What happens if a one-time extra is larger than the remaining balance?

The calculator caps the remaining principal at zero. If a one-time extra equals or exceeds the remaining balance, payoff is immediate and the estimated remaining payments will be zero.

Sources & citations

Further resources

External guidance

Versioning & Change Control

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

Record ID: 7c6b99d7a1f7

What changed (latest)

v1.0.0 • 2025-11-17 • 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 17, 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 • 2025-11-17 • 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: ff9e798baa34