Revenue Logic and Basic Unit Economics
10 min read
Lesson objectives
- Calculate order contribution before and after acquisition cost from explicit assumptions.
- Distinguish order-linked variable cost from fixed cost in a simplified model.
- Use simple break-even and weighted-average calculations while testing the limits of assumptions.
Turn “sales” into the economics of one order
Revenue alone does not tell you whether an order contributes economically. At a foundational level, we can define the **unit** as one order and separate flows directly associated with that order from fixed costs. This is not a substitute for financial accounting or an income statement; it is a simplified decision tool for understanding the effects of price, variable cost, and customer acquisition before aggregating thousands of orders. The unit, time period, and cost scope must be explicit so the numbers do not become misleading comparisons.
Order contribution before acquisition cost = order revenue − variable product/service cost − variable processing fees − variable shipping/fulfilment subsidy − other direct variable costs.
Order contribution after acquisition cost = contribution before acquisition − acquisition cost attributed to that order.
| Item | Included in order contribution here? | Why |
|---|---|---|
| Merchandise cost for the order | Yes | It varies with the order in this example. |
| Processing fee charged as a share of the order | Yes | It is a variable transaction cost. |
| Shipping subsidy paid for this order | Yes | It is directly tied to fulfilment of the order. |
| Monthly office rent | Not in this metric | It is treated as fixed here and considered later in break-even/overall results. |
| Fixed team salary | Not in this simplified order contribution | It does not vary directly with each order under the current assumption. |
| Advertising spend attributed to this order | Subtract when calculating contribution after acquisition | An explicit attribution rule is needed rather than mixing it arbitrarily into every order. |
The result changes when the definition changes. One team may calculate acquisition cost per “new customer” at campaign level while another calculates it per “order”; one may include full shipping while another includes only the amount subsidised after the customer charge. Two metrics with the same name are not comparable if their scopes differ. Always write the numerator, denominator, and period—for example, “attributed campaign spend ÷ attributed new customers during the period”—and state the attribution limits.
From one order to a simple break-even view
If contribution after acquisition is assumed constant and fixed costs do not change within the relevant range: approximate orders to cover fixed cost = fixed costs ÷ contribution per order.
Lesson summary
Unit economics is a simplified decision tool: define the unit and scope, calculate contribution clearly, then test cost and capacity changes before generalising the result.