LTV:CAC Ratio
The LTV:CAC ratio compares the value generated by a customer relationship with the cost of acquiring that customer.
What is LTV:CAC Ratio?
The ratio expresses how many units of customer value correspond to one unit of acquisition cost. A 2:1 ratio means the stated LTV is twice the stated CAC. Its usefulness depends on how both inputs were calculated.
For ecommerce profitability, a contribution-based LTV before acquisition creates a clearer comparison than lifetime revenue. Gross-profit-based or revenue-based versions need their own labels because they leave different costs outside the numerator.
LTV:CAC ratio = Customer lifetime value ÷ Customer acquisition cost
Use the same customer population, currency and acquisition definition. State the LTV horizon and value basis. CAC must be positive for the ordinary ratio to be meaningful.
Reading a 2.5:1 relationship
A new-customer cohort is expected to produce $125 of contribution per customer over 24 months, before acquisition. Its CAC is $50. The LTV:CAC ratio is $125 ÷ $50 = 2.5:1. After acquisition, expected contribution is $75 per customer before fixed costs; the ratio itself is not a net profit margin.
How to interpret it
A ratio above 1:1 means the specified value exceeds acquisition cost. It does not establish that the company is profitable. Fixed expenses, uncertainty and the timing of the expected value still need consideration. If the numerator is revenue, even the product costs remain uncovered by this comparison.
The same ratio can describe very different cash demands. A customer generating most contribution in one month is different from one generating it over three years. Read the ratio with acquisition payback and available funding rather than treating it as a complete scaling signal.
There is no universal target that removes these differences. Product category, return patterns, retention evidence and the cost boundary influence what a ratio means. A widely quoted benchmark should not override the specific economics of the cohort.
An exceptionally high ratio is not automatically evidence that advertising should be increased. It may result from excluding acquisition costs, overestimating future purchases or measuring only retained customers. It may also describe a small audience whose economics do not persist at higher spend.
The numerator decides the meaning
Suppose customer revenue is $300 but contribution before acquisition is only $90, with CAC of $30. The revenue-based ratio is 10:1; the contribution-based ratio is 3:1. Neither division is an arithmetic error. They answer different economic questions because the second has already recognized variable service costs. A report that presents the first as if it were the second substantially overstates the resources available after acquisition. Include the value basis in the metric label whenever the ratio leaves its original report.
Common mistakes
Deducting CAC inside LTV and comparing it with CAC again
For the conventional value-to-acquisition comparison, use LTV before acquisition. A post-acquisition numerator describes a different ratio and needs a different label.
Comparing unmatched cohorts
A mature organic cohort’s value and a new paid cohort’s acquisition cost do not form a coherent ratio. Match the population and disclose forecast assumptions.