Plain definition
The LTV-to-CAC ratio compares estimated customer lifetime value with customer acquisition cost. It is useful only after both terms are defined. LTV may mean revenue, gross margin, or contribution after direct service costs; CAC may include different sales and marketing costs. A revenue-based LTV divided by CAC is not a profit-based return.
There is no universal target ratio. A ratio can look strong because the lifetime is assumed too long, because service costs were excluded, or because recent acquisition spend has not yet been matched to acquired customers. The comparison should use cohorts that share an acquisition period, channel, and economics.
Illustrative example
Monetary examples use Saudi riyals (SAR). The same principles apply in other currencies.
Suppose a customer is expected to generate of annual revenue for three years and direct service costs consume a year. Contribution-based LTV is , not revenue. If matched CAC is , the contribution LTV-to-CAC ratio is 1.5 times.
That result starts a question: will retention, price, and service cost support it? It does not supply an automatic pass or fail. A company with scarce cash may still reject a 1.5-times case if contribution arrives too slowly.
| Revenue over three years (SAR 400 × 3) | |
|---|---|
| Direct service costs (SAR 50 × 3) | |
| Contribution LTV |
| Contribution LTV | |
|---|---|
| Matched CAC | |
| Contribution LTV-to-CAC ratio |
Label both the LTV basis and the CAC basis every time the ratio is reported.
This simplified example uses undiscounted contribution and assumes three years of retention. A longer or less certain customer life needs an explicit retention model and consideration of discounting.
Why it matters
The ratio links growth spending to the economics it is meant to create. Without matched definitions it can turn two attractive labels into a misleading investment claim.
Practical consequence
Calculate LTV from observed cohort retention and a stated contribution basis where possible. Match the CAC spend and customers by channel and period. Show revenue LTV separately from gross-margin or contribution LTV, test shorter lifetime and higher service cost, and pair the ratio with CAC payback and cash headroom.