---
name: unit-economics
description: Use when asked to analyze or explain the profitability of a business at the level of one customer or unit — lifetime value, acquisition cost, contribution margin — as distinct from a full financial model or [[roi-analysis]] of a single project or investment.
---

# Unit Economics

Unit economics measures whether a business makes or loses money on one
customer, one order, or one unit of whatever it sells, stripped of
company-wide overhead. It answers a narrower question than "is the
company profitable": does each additional unit sold move the business
toward profitability or away from it.

## Key metrics

- **Customer acquisition cost (CAC)** — the fully loaded cost to acquire
  one paying customer: ad spend, sales salaries and commissions,
  marketing overhead, and any tools or agency fees involved in
  acquisition, divided by the number of customers acquired in that
  period.
- **Customer lifetime value (LTV)** — the total contribution margin a
  customer is expected to generate over the whole time they stay a
  customer, not just their first purchase.
- **LTV:CAC ratio** — LTV divided by CAC; a common rule of thumb targets
  roughly 3:1 or higher, though the right target varies by business
  model, margin structure, and how fast CAC is recovered.
- **Contribution margin per unit** — revenue per unit minus the variable
  costs directly tied to producing or delivering that unit (see
  [[break-even-analysis]] for how this feeds a break-even calculation).
- **Payback period** — how many months of a customer's contribution
  margin it takes to recover their CAC; a short payback period matters
  even when the LTV:CAC ratio looks healthy, because it determines how
  much cash the business needs to fund growth.

## Why aggregate growth can hide unit-level losses

Revenue growing month over month can mask the fact that the business
loses money on every single customer it adds — growth is just adding
more losing units faster. A business can look impressive on top-line
revenue while its unit economics are negative, and the faster it grows
under that condition, the faster it burns cash. Unit economics is the
check that catches this before it shows up as a cash crisis: profitable
growth and mere revenue growth are different things, and only unit-level
numbers distinguish them.

## Where the numbers come from

CAC and LTV are only useful if their inputs are complete and consistent
with each other. Pull acquisition costs from the same time period as the
customers they acquired (not the period they happened to be paid), and
define "customer" the same way in both the CAC and LTV calculations —
mixing a broad definition in one and a narrow one in the other silently
inflates the ratio.

## Common pitfalls

- **CAC that excludes real costs** — counting only ad spend and leaving
  out sales salaries, commissions, or marketing team overhead
  understates CAC and makes the ratio look better than the business
  actually is.
- **LTV projected over an unrealistic retention period** — assuming
  customers stay five years when actual cohort data shows most churn
  within one inflates LTV and the resulting ratio.
- **Small early cohort treated as representative** — a ratio calculated
  on the first handful of customers (often early adopters or
  founder-network referrals with atypically low CAC and high loyalty)
  rarely holds once the business scales to a broader, less
  self-selected market.
- **Ignoring payback period** — a strong LTV:CAC ratio with a
  three-year payback period can still starve the business of cash long
  before the value is realized.
- **Blending very different customer segments into one number** — a
  single average CAC or LTV across segments with very different
  behavior hides that one segment is highly profitable and another is
  quietly losing money.
- **Confusing contribution margin with gross margin** — leaving
  variable delivery or support costs out of the per-unit calculation
  overstates how much each unit actually contributes.

## Learn more

- [[break-even-analysis]] for finding the volume at which total
  contribution margin covers fixed costs.
- [[roi-analysis]] for evaluating a single project or investment rather
  than a per-customer or per-unit economic pattern.
- [[budget-forecasting]] for projecting these unit-level numbers forward
  into a company-wide financial plan.
- [[business-model-canvas]] for the broader business-model context unit
  economics is one input into.