Glossary
What is Customer Acquisition Cost (CAC)?
Customer Acquisition Cost is the total sales and marketing spend required to acquire one new paying customer over a given period, calculated as total acquisition spend divided by the number of new customers gained.
CAC is deliberately a blended, business-level number, not a single channel's cost-per-lead — it should include ad spend, but also the cost of the people and tools running that spend, since a channel that looks cheap on a platform dashboard can be expensive once the labor to manage it is counted honestly.
CAC only means something next to Customer Lifetime Value (CLV). A $200 CAC is a problem for a product with a $150 average lifetime value and a healthy number for one with a $3,000 lifetime value — the ratio between the two, not either number alone, is what determines whether a given acquisition channel is actually sustainable to keep funding.
A common distortion is measuring CAC only against last-touch conversions from a single ad platform, which understates the real number whenever multiple channels (organic search, paid social, referral) work together across a longer buying journey — the same attribution problem the Signal-to-Revenue Framework's reconciliation stage exists to correct.