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Methodology

Business Loan Repayment Planner methodology

Estimate scheduled repayments, total interest and the effect of changing the loan term or balloon payment.
Duc Nguyen X.By Duc Nguyen X.· Founder, Margin101Last reviewed: View update historyMethodology

Educational only: Business decision support, not accounting, tax or legal advice.

Privacy: Calculations run locally; Margin101 does not receive your commercial inputs.

Update policy: Reviewed when formulas or official dependencies change.

Scope: Market-neutral small-business planning using your own assumptions.

1. Formulas and units

Periodic Payment
periodicPayment = amortised principal × periodic rate ÷ (1 − (1 + periodic rate)^−payments)

Where

principal
Loan principal (currency units of opening loan principal)Source: Business record
totalPayments
Total payments (whole scheduled payment periods/loan term)Source: Business record
periodicPayment
Periodic Payment (currency units, ex tax)Source: Calculated output
totalPayments
Total scheduled payments (whole-number count)Source: User assumption
Total Scheduled Payments
totalScheduledPayments = periodic payment × total payments + balloon payment

Where

totalPayments
Total payments (whole scheduled payment periods/loan term)Source: Business record
balloonPayment
Final balloon payment (currency units due with the final scheduled payment)Source: Business record
periodicPayment
Periodic Payment (currency units, ex tax)Source: Calculated output
totalScheduledPayments
Total Scheduled Payments (currency units, ex tax)Source: Calculated output
totalPayments
Total scheduled payments (whole-number count)Source: User assumption
Total Interest
totalInterest = total scheduled payments − principal

Where

principal
Loan principal (currency units of opening loan principal)Source: Business record
totalPayments
Total payments (whole scheduled payment periods/loan term)Source: Business record
totalScheduledPayments
Total Scheduled Payments (currency units, ex tax)Source: Calculated output
totalInterest
Total Interest (currency units, ex tax)Source: Calculated output
totalPayments
Total scheduled payments (whole-number count)Source: User assumption
Payment Count
paymentCount = number of scheduled payments

Where

totalPayments
Total payments (whole scheduled payment periods/loan term)Source: Business record
totalScheduledPayments
Total Scheduled Payments (currency units, ex tax)Source: Calculated output
paymentCount
Payment Count (operational units)Source: Calculated output
totalPayments
Total scheduled payments (whole-number count)Source: User assumption
Final Closing Principal
finalClosingPrincipal = closing principal after final payment

Where

principal
Loan principal (currency units of opening loan principal)Source: Business record
finalClosingPrincipal
Final Closing Principal (currency units, ex tax)Source: Calculated output
Equipment financed amount
financedAmount = purchasePrice − deposit

Where

purchasePrice
Equipment purchase price (currency units, ex tax)Source: User assumption
deposit
Deposit paid at purchase (currency units, ex tax)Source: User assumption
Initial cash required
initialCashRequired = deposit

Where

deposit
Deposit paid at purchase (currency units, ex tax)Source: User assumption
Equipment periodic payment
periodicPayment = canonical amortising loan payment for financedAmount, periodic rate, payment count and residualPayment

Where

periodicPayment
Periodic Payment (currency units, ex tax)Source: Calculated output
paymentCount
Payment Count (operational units)Source: Calculated output
residualPayment
Residual payment (currency units, ex tax)Source: User assumption
Scheduled finance payments
totalScheduledPayments = periodicPayment × totalPayments + residualPayment

Where

totalPayments
Total payments (whole scheduled payment periods/loan term)Source: Business record
periodicPayment
Periodic Payment (currency units, ex tax)Source: Calculated output
totalScheduledPayments
Total Scheduled Payments (currency units, ex tax)Source: Calculated output
totalPayments
Total scheduled payments (whole-number count)Source: User assumption
residualPayment
Residual payment (currency units, ex tax)Source: User assumption
Equipment total interest
totalInterest = totalScheduledPayments − financedAmount

Where

totalPayments
Total payments (whole scheduled payment periods/loan term)Source: Business record
totalScheduledPayments
Total Scheduled Payments (currency units, ex tax)Source: Calculated output
totalInterest
Total Interest (currency units, ex tax)Source: Calculated output
totalPayments
Total scheduled payments (whole-number count)Source: User assumption
Equipment total cash outflow
totalCashOutflow = deposit + totalScheduledPayments

Where

totalPayments
Total payments (whole scheduled payment periods/loan term)Source: Business record
totalScheduledPayments
Total Scheduled Payments (currency units, ex tax)Source: Calculated output
deposit
Deposit paid at purchase (currency units, ex tax)Source: User assumption
totalPayments
Total scheduled payments (whole-number count)Source: User assumption

Money inputs and outputs use the currency selected in the scenario without changing the canonical methodology. Rates, margins, utilisation and buffers are entered as percentages and converted to decimal values for calculation.

2. Worked example

Input assumptions

The worked rows below come directly from the registered engine and visible default fixture.

Calculation and outputs

Example

The worked rows below come directly from the registered engine and visible default fixture.

Periodic Payment
5,009.49 currency units
Total Scheduled Payments
300,569.23 currency units
Total Interest
50,569.23 currency units
Payment Count
60
Final Closing Principal
0 currency units
Equipment financed amount
100,000 currency units
Initial cash required
20,000 currency units
Equipment payment each period
1,865.92 currency units
Scheduled finance payments
121,954.92 currency units
Equipment total interest
21,954.92 currency units
Equipment total cash outflow
141,954.92 currency units

The exact engine-derived outputs are shown in the labelled rows below.

Interpretation

Treat the schedule as an estimate that must be reconciled with lender fees, timing conventions and contract terms.

3. Validation and boundary checks

  • All inputs must be finite and within the visible boundaries.
  • Cash, debt and timing values use one consistent planning period.
  • Payment counts and frequencies must be positive whole numbers.

4. Assumptions and source classification

  • All balances, rates, timing and coverage thresholds are user-supplied records or explicit assumptions.
  • No lender covenant, market rate, policy threshold or future cash flow is inferred.

This planner has no current policy-data dependency. Its commercial assumptions are user supplied. Registered family-level regression suites exercise the shared business-logic engine and worked-result reconciliation.

5. Limitations

  • The model excludes lender fees, taxes, covenant definitions and lender-specific credit assessments.
  • It does not replace accounting, tax, legal or financial advice.

This is educational decision support, not tax, accounting, legal or financial advice. Check the treatment of your actual transactions under the rules that apply to your business and seek qualified advice where appropriate.

6. Update and evidence policy

Registered family-level suites test formula invariants and example reconciliation; the release ledger records that coverage without claiming a separate oracle for every line of public copy. There is no official threshold or benchmark to refresh for this planner. Commercial inputs remain user-supplied because they vary by business and contract.

Change history

  1. : Initial public release of the Business Loan Repayment planner and methodology.

Related reading

Guides to interpret the decision and its assumptions.

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