ユニットエコノミクス

Unit economics breaks a business into revenue, variable cost, acquisition cost, and retention value per unit. It prevents teams from scaling a model where each additional customer or order destroys value. Unit Economics should be read through the decision it informs, the assumptions behind it, and the action that changes it. This page treats the term as an operating decision metric: it fixes the formula, boundaries, drivers, companion metrics, and comparison points so teams can interpret the number consistently. Use it with an explicit period, segment, owner, and data source rather than as a dictionary label.

Basic formula: unit profit = unit revenue - unit variable cost - unit acquisition cost. In SaaS, also read LTV/CAC and CAC payback. Formula | Basic formula: unit profit = unit revenue - unit variable cost - unit acquisition cost. In SaaS, also read LTV/CAC and CAC payback. | Use it as the primary operating calculation Bridge | Beginning unit profit + price improvement - variable-cost change - CAC change + retention improvement = revised unit profit | Use it to explain changes between reviews Segment | Split by customer, product, channel, and period | Use it to find deterioration hidden by averages

This metric is comparable only when inclusion and exclusion rules stay stable. Include | Unit revenue, variable cost, payment, delivery, support, CAC, retention | They determine per-unit value Exclude | Crude corporate fixed-cost allocation, hoped-for future efficiency | They obscure current unit economics Define explicitly | Customer vs order, first purchase vs repeat purchase | The unit changes the conclusion

Breaking the metric into drivers clarifies what action should follow the review. ARPU or price | Determines revenue per unit Variable cost | Determines cost that scales with volume CAC and retention | Determine whether acquisition can be recovered

Determines whether to scale, pause, or redesign the business model. Guides pricing and cost-structure changes to improve contribution margin. Informs marketing spend limits based on per-customer profitability.

• Determines whether to scale, pause, or redesign the business model.
• Guides pricing and cost-structure changes to improve contribution margin.
• Informs marketing spend limits based on per-customer profitability.

• Positive unit economics are required before aggressive scaling.
• Variable costs, not fixed costs, are the focus for unit analysis.
• Improving retention and upsells can strengthen unit profitability.
• Break-even on a unit basis signals whether growth will be healthy.
• Unit economics should be reviewed by segment, not only in aggregate.

Do not decide from the number alone; align assumptions, period, segments, and companion metrics. Average units can hide unprofitable segments. Do not ignore fixed costs when discussing company profitability. Optimistic LTV assumptions can overjustify CAC spend.

• Average units can hide unprofitable segments.
• Do not ignore fixed costs when discussing company profitability.
• Optimistic LTV assumptions can overjustify CAC spend.

Companion metrics turn a good-or-bad reading into a discussion of causes and actions. CAC | Acquisition cost | Consumes unit profit LTV | Customer lifetime value | Tests CAC recovery Contribution Margin | Profit after variable costs | Core of unit profitability

A subscription has $40 monthly gross profit, $240 CAC, and 5% monthly churn. Simple payback is six months and expected average life is about 20 months. By channel, one source has much longer payback, so the team pauses it until retention improves. After the review, the owner did not treat the metric in isolation. They compared it with companion metrics, checked segment differences, documented assumption changes, and verified data quality before changing the plan. Whether the number improved or deteriorated, the team identified the driver, assigned an owner, and fed the learning into the next budget, operating review, or experiment cycle.

Gross margin | Product-level margin | Unit economics also includes acquisition and retention BEP | Fixed-cost recovery threshold | Unit profit informs required volume ARR | Recurring revenue scale | Unit economics tests quality of that revenue

• High revenue means healthy units; margins could still be negative.
• Unit economics is only for startups; mature firms also need it.
• One average unit is enough; segment variation can hide losses.