Fidamen

Home Loan Balloon Payment Calculator with Extra Payments

This calculator estimates the amount due at a balloon date for a home loan and shows how recurring extra principal payments change that balance. It supports common payment frequencies and allows you to override the scheduled payment if your loan has a nonstandard payment amount.

Results are produced using closed-form amortization formulas and an adjusted-payment approximation when recurring extras are included. Because servicer rules, compounding conventions, and rounding can vary, consider the output an estimate for planning; always confirm exact payoffs with your lender.

Updated Nov 15, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 2a5803b1c363 • Reviewed by Fidamen Standards Committee

Compute the periodic payment assuming full amortization over the loan term and the remaining principal (balloon) at the balloon date, without extra principal prepayments.

Inputs

Results

Updates as you type

Regular periodic payment

$1,432.25

Balloon amount due

$271,342.54

Interest paid through balloon date

$57,277.29

OutputValueUnit
Regular periodic payment$1,432.25—
Balloon amount due$271,342.54—
Interest paid through balloon date$57,277.29—
Primary result$1,432.25

Visualization

Methodology

Periodic interest rate is computed as APR divided by payment frequency. The scheduled payment uses the standard level-payment amortization formula for the chosen amortization term. The balloon balance after N payments is calculated from the remaining principal formula: principal grown by periodic compounding minus the accumulated effect of payments.

For recurring extra principal payments we use an adjusted-payment closed-form approximation by treating the extra principal as an additional fixed payment each period. This produces a close estimate in typical consumer scenarios but does not model complex conditional start/stop schedules, escrow advances, payment holidays, or servicer rounding rules.

Worked examples

Example 1: $300,000 loan, 4.0% APR, 30-year amortization, balloon at 5 years (monthly). The calculator shows the scheduled monthly payment, the remaining principal after 60 payments, and interest paid to that date.

Example 2: Same loan but adding $200 extra principal each month; the calculator provides an estimated lower balloon balance and estimated interest savings relative to no extras.

F.A.Q.

Does this exact payoff match my lender's payoff statement?

Not always. This tool uses standard amortization math and a closed-form approximation for recurring extra payments. Lenders apply their own rounding, interest accrual day-count conventions, escrow advances, fees, and prepayment application order. Always request a formal payoff from your servicer before making final arrangements.

Are one-time extra payments modeled?

This version focuses on recurring extra principal applied each payment. A one-time extra reduces principal immediately and will reduce subsequent interest; for precise one-time impacts, use the extra amount as a recurring extra for one period and consult your servicer for exact posting rules.

Why might results differ when I change payment frequency?

Payment frequency changes the periodic interest rate and compounding intervals. Equivalent APRs produce slightly different periodic accruals depending on frequency; comparison should use the same frequency used by your loan contract.

What are the limits and accuracy considerations?

This tool is accurate for standard fixed-rate, level-payment amortization and for recurring fixed extras. It is an approximation when extras start after a delay or stop before the balloon, or when loans have negative amortization features, variable rates, or nonstandard compounding. See citations for standards on numeric accuracy and testing.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: 2a5803b1c363

What changed (latest)

v1.0.0 • 2025-11-15 • 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 15, 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 • 2025-11-15 • 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: 2e21b33a8769