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Methodology

Annual vs Monthly Plan Planner methodology

Compare upfront annual cash and expected contribution with a 12-month retention-weighted monthly cohort.
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

Expected monthly-plan cash
expectedMonthlyPlanCash = monthly price × sum of 12 retained shares

Where

monthlyPrice
Monthly price (currency units on one consistent basis)Source: Business record
expectedMonthlyPlanCash
Expected monthly-plan cash (money)Source: Calculated output
Expected monthly-plan contribution
expectedMonthlyPlanContribution = monthly cash after fees − retained service cost − acquisition cost

Where

monthlyServiceCost
Monthly service cost (currency units on one consistent basis)Source: Business record
acquisitionCost
Acquisition cost (currency units on one consistent basis)Source: Business record
expectedMonthlyPlanCash
Expected monthly-plan cash (money)Source: Calculated output
expectedMonthlyPlanContribution
Expected monthly-plan contribution (money)Source: Calculated output
Annual-plan upfront cash
annualPlanUpfrontCash = monthly price × 12 × (1 − annual discount)

Where

monthlyPrice
Monthly price (currency units on one consistent basis)Source: Business record
annualPlanUpfrontCash
Annual-plan upfront cash (money)Source: Calculated output
Expected annual-plan cash after refunds
expectedAnnualPlanCash = annual upfront cash × (1 − annual refund rate)

Where

annualRefundRate
Annual refund rate (decimal rate)Source: Business record
annualPlanUpfrontCash
Annual-plan upfront cash (money)Source: Calculated output
expectedAnnualPlanCash
Expected annual-plan cash after refunds (money)Source: Calculated output
Expected annual-plan contribution
expectedAnnualPlanContribution = expected annual cash after annual payment fee − 12 months of service cost − acquisition cost

Where

acquisitionCost
Acquisition cost (currency units on one consistent basis)Source: Business record
expectedAnnualPlanCash
Expected annual-plan cash after refunds (money)Source: Calculated output
expectedAnnualPlanContribution
Expected annual-plan contribution (money)Source: Calculated output
Annual contribution difference
annualContributionDifference = annual contribution − monthly contribution

Where

annualContributionDifference
Annual contribution difference (money)Source: Calculated output

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

Worked values below come from the same registered engine and visible default assumptions.

Calculation and outputs

Example

Worked values below come from the same registered engine and visible default assumptions.

Expected monthly-plan cash
1,200.00 currency units
Expected monthly-plan contribution
824.00 currency units
Annual-plan upfront cash
1,080.00 currency units
Expected annual-plan cash after refunds
1,080.00 currency units
Expected annual-plan contribution
707.60 currency units
Annual contribution difference
-116.40 currency units

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

Interpretation

Use the contribution difference alongside cash timing; upfront annual cash is not the same as recognised revenue or earned profit.

3. Validation and boundary checks

  • Exactly 12 finite non-increasing retention shares are required between 0% and 100%.
  • Annual discount, annual fee and monthly fee rates must be finite and remain below 100%.
  • Annual upfront cash is derived once from monthly price × 12 × (1 − annual discount).
  • Annual contribution always subtracts 12 months of service cost, including at a 100% price refund.
  • Contribution difference reconciles annual contribution less retention-weighted monthly contribution.

4. Assumptions and source classification

  • Retention weights describe one opening cohort.
  • Annual and monthly payment fee rates are separately entered contract assumptions with no provider default.
  • The refund rate reduces annual cash, not the assumed 12 months of service delivery; cancellation timing is not modelled.

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 owner and embedded discount module are planning comparisons, not revenue-recognition or contract advice.
  • It does not replace financial, accounting, tax or legal 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 planner and methodology after pre-launch calculation, content, source and interaction review.

Related reading

Guides to interpret the decision and its assumptions.

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