Agency Retainer Margin Planner methodology

plannedLabourCostExTax = sum(planned role hours * loaded role cost)

scopeCreepCostExTax = sum(scope-creep role hours * loaded role cost)

deliveryCostExTax = planned labour + scope creep labour + third-party cost

plannedHours = sum planned role hours

scopeCreepHours = sum unscoped role hours

capacityUtilisationRate = (planned + scope-creep hours) / available role hours

contributionExTax = monthly retainer - total delivery cost

contributionMargin = contribution / monthly retainer

requiredRetainerExTax = total delivery cost / (1 - target margin)

repricingGapExTax = required retainer - current retainer

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.

• All inputs must be finite and inside the visible validation boundaries.
• Rates are retained as decimal values and shown as percentages only at the presentation boundary.
• The worked fixture must expose every declared result: plannedLabourCostExTax, scopeCreepCostExTax, deliveryCostExTax, plannedHours, scopeCreepHours, capacityUtilisationRate, contributionExTax, contributionMargin, requiredRetainerExTax, repricingGapExTax.
• Scenario comparison changes one declared driver while holding the remaining industry records constant.

Current monthly retainer minimum

monthlyRetainerExTax ≥ 0 currency units/client/month, ex tax — A lower value is rejected before calculation.

Current monthly retainer maximum

monthlyRetainerExTax ≤ 10,000,000 currency units/client/month, ex tax — A higher value is rejected before calculation.

Strategy and account planned hours minimum

strategyPlannedHours ≥ 0 hours/client/month — A lower value is rejected before calculation.

Strategy and account planned hours maximum

strategyPlannedHours ≤ 100,000 hours/client/month — A higher value is rejected before calculation.

Strategy and account scope-creep hours minimum

strategyScopeCreepHours ≥ 0 hours/client/month — A lower value is rejected before calculation.

Strategy and account scope-creep hours maximum

strategyScopeCreepHours ≤ 100,000 hours/client/month — A higher value is rejected before calculation.

Strategy and account loaded cost per hour minimum

strategyLoadedCostPerHourExTax ≥ 0 currency units/hour, ex tax — A lower value is rejected before calculation.

Strategy and account loaded cost per hour maximum

strategyLoadedCostPerHourExTax ≤ 10,000,000 currency units/hour, ex tax — A higher value is rejected before calculation.

Strategy and account available hours minimum

strategyAvailableHours ≥ 0 hours/client/month — A lower value is rejected before calculation.

Strategy and account available hours maximum

strategyAvailableHours ≤ 100,000 hours/client/month — A higher value is rejected before calculation.

Creative and delivery planned hours minimum

deliveryPlannedHours ≥ 0 hours/client/month — A lower value is rejected before calculation.

Creative and delivery planned hours maximum

deliveryPlannedHours ≤ 100,000 hours/client/month — A higher value is rejected before calculation.

Creative and delivery scope-creep hours minimum

deliveryScopeCreepHours ≥ 0 hours/client/month — A lower value is rejected before calculation.

Creative and delivery scope-creep hours maximum

deliveryScopeCreepHours ≤ 100,000 hours/client/month — A higher value is rejected before calculation.

Creative and delivery loaded cost per hour minimum

deliveryLoadedCostPerHourExTax ≥ 0 currency units/hour, ex tax — A lower value is rejected before calculation.

Creative and delivery loaded cost per hour maximum

deliveryLoadedCostPerHourExTax ≤ 10,000,000 currency units/hour, ex tax — A higher value is rejected before calculation.

Creative and delivery available hours minimum

deliveryAvailableHours ≥ 0 hours/client/month — A lower value is rejected before calculation.

Creative and delivery available hours maximum

deliveryAvailableHours ≤ 100,000 hours/client/month — A higher value is rejected before calculation.

Third-party delivery cost minimum

thirdPartyDeliveryCostExTax ≥ 0 currency units/client/month, ex tax — A lower value is rejected before calculation.

Third-party delivery cost maximum

thirdPartyDeliveryCostExTax ≤ 10,000,000 currency units/client/month, ex tax — A higher value is rejected before calculation.

Target retainer margin minimum

targetRetainerMargin ≥ 0 decimal fraction of monthly retainer revenue — A lower value is rejected before calculation.

Target retainer margin maximum

targetRetainerMargin ≤ 0.99 decimal fraction of monthly retainer revenue — A higher value is rejected before calculation.

• Costs, capacity, contract terms, tax rates and targets are supplied by the user.
• No provider default, jurisdictional rule or industry benchmark is embedded.
• The shared engine retains full precision and display formatting never feeds calculation.

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.

• Results are only as reliable as the timing, scope and basis of the entered records.
• The workflow does not predict demand or establish accounting, tax, contractual or legal treatment.

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.

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.

1. 2026-07-16: Initial public release of the Agency Retainer Margin planner and methodology.