The total sales and marketing spend required to acquire one new customer. CAC is the primary efficiency metric for go-to-market investment, evaluated against Customer Lifetime Value (LTV) to assess long-run return on growth spending.
Also known as:
CAC, cost per acquisition, cost to acquire
Customer Acquisition Cost (CAC) is the total sales and marketing spend required to acquire one new customer. It is calculated by dividing total sales and marketing expenditure over a period by the number of new customers acquired in that period. CAC is the primary efficiency metric for go-to-market investment and is routinely evaluated against Customer Lifetime Value (LTV) to determine the long-run return on growth spending.
A common mistake is to exclude fully-loaded costs — salaries, benefits, tools, agency fees, and overhead — from the CAC calculation, producing a figure that understates the true cost of acquisition. Fully-loaded CAC divides all sales and marketing costs (people, programmes, and technology) by new customers acquired. The period used matters too: if sales cycles are long, using a quarter's spend against that quarter's new customers produces a distorted figure — a rolling 12-month average is more accurate for businesses with 6-month+ sales cycles.
CAC in isolation tells you the input cost. Comparing it to LTV (the total revenue expected from a customer over their relationship with the business) tells you whether the acquisition is profitable. An LTV:CAC ratio of 3:1 is commonly cited as a healthy benchmark for B2B SaaS — meaning the customer generates three times the cost of acquiring them. Ratios below 1:1 mean the business is acquiring customers at a loss. Ratios significantly above 3:1 may indicate under-investment in growth.
Aggregate CAC masks meaningful variation. CAC from inbound leads is typically much lower than CAC from outbound-sourced deals. CAC for SMB customers is typically lower than enterprise, though LTV may also be lower. Breaking CAC down by channel, segment, and cohort reveals which parts of the go-to-market motion are efficient and which are not — and allows investment to be concentrated where returns are highest.
CAC falls when qualification improves (less time spent on deals that don't close), sales cycles shorten, close rates increase, or marketing generates higher-intent leads at lower cost. Sustainable CAC reduction comes from improving the system — not from cutting spend in ways that also reduce pipeline. Teams that cut marketing to hit short-term cost targets often see CAC rise in subsequent quarters as the pipeline effect of reduced investment flows through.
Customer Acquisition Cost is a primary lens in the commercial model work we do in Closing OS engagements. When a founder describes their go-to-market investment and asks whether it is working, CAC by channel and segment is one of the first calculations we make — it reveals whether the return on growth spending is sustainable and which parts of the sales and marketing motion are efficient. We also use CAC to calibrate headcount decisions: a team considering whether to hire its first SDR needs to model whether the CAC of SDR-sourced pipeline is competitive with the CAC from other channels. In Revenue Planning work, fully-loaded CAC is one of the three financial model inputs (alongside ACV and LTV) that determines the viable growth rate.
In 60 minutes, get a clearer view of what to fix or build first. A no-cost operator-led working session for founder-led teams and revenue leaders.