CAC (Customer Acquisition Cost)

CAC (Customer Acquisition Cost) is the metric that answers a simple but decisive question: how much do you spend, on average, to add a new customer? You get it by adding up everything invested in marketing and sales over a period (ad spend, sales team salaries, tools, agencies) and dividing it by the number of customers acquired in that same period.

Its basic formula is CAC = (marketing spend + sales spend) / new customers. If in one quarter your company spent ARS 3 million (Argentine pesos) on ads and the sales team and closed 30 customers, your CAC was ARS 100,000 per customer. The number on its own does not tell you whether it is good or bad: it only makes sense when you compare it against how much that customer is worth over time.

Calculating CAC correctly requires a single source of truth that matches real spend against actual conversion, which is why it lives on the analytics and BI side, part of what Metrix brings order to. Without that consolidation, every department reports a different number and decisions are made blind.

How it is calculated (and what goes into the calculation)

The most common trap is not the formula, but which costs you include. An honest CAC adds up all the costs attributable to acquisition: advertising spend, salaries and commissions of the marketing and sales team, software licenses (CRM, marketing automation, prospecting tools), agency fees and content production. If you only count ad spend and leave salaries out, you will underestimate CAC and believe you are more profitable than you are.

A key distinction is between blended CAC and CAC by channel. Blended CAC divides total spend by all new customers, regardless of where they came from, and includes organic traffic and referrals that cost nothing. CAC by channel isolates each source (Google Ads, Meta, outbound, events) to see which one brings you cheaper customers. Both are useful: blended for understanding overall health, by channel for deciding where to put your next dollar.

Why it matters for the business

CAC is half of the profitability equation. The other half is LTV, the value that customer generates over the entire relationship with you. The relationship between the two, known as the LTV:CAC ratio, is one of the most closely watched indicators in any recurring-revenue business: Bessemer Venture Partners recommends investing in acquisition when that ratio is 3:1 or higher, that is, when the customer returns at least three times what it cost to acquire (Scaling to $100 Million, 2021). Below 1:1, every sale loses you money; above 3:1, it pays to invest more in growth.

CAC also determines the CAC payback period, meaning how many months it takes you to recover what you invested to win the customer. In subscription or recurring-revenue companies, a long payback forces you to fund growth for longer, which strains cash flow even if the business is healthy in the long run.

Common mistakes when measuring it

• Mixing the spend period with the conversion period: if you invest heavily in advertising this month but those customers only close two months from now, dividing this month's spend by this month's customers artificially inflates CAC. It is better to look at wider windows or cohorts.
• Forgetting team costs: counting only ad spend and not sales salaries is the most frequent mistake and the one that distorts the most.
• Ignoring the channel: a healthy average CAC can hide one channel that loses money and another that saves it. Without segmenting by marketing attribution, you do not know which is which.

A concrete example (Argentina)

An Argentine B2B company that sells business management software invests each month: ARS 1,500,000 in Google Ads and Meta, ARS 2,000,000 in salaries for two sales reps and a marketing specialist, and ARS 300,000 in CRM licenses and tools. Total: ARS 3,800,000. That month it closed 19 new customers. Its blended CAC is ARS 200,000 per customer. If each customer pays ARS 80,000 per month on average and stays for 18 months, its LTV is around ARS 1,440,000 (before service costs), which gives an LTV:CAC ratio of roughly 7:1: very comfortable, a sign that it could invest more aggressively in acquisition without putting profitability at risk.

CAC vs CPL: they are not the same

A frequent mistake is confusing the cost of acquiring a customer with the cost of generating a lead. They are different metrics at different moments of the funnel.

A low CPL does not guarantee a low CAC: you can generate cheap leads that almost never close and end up with a sky-high CAC. That is why CAC is always read alongside the funnel's conversion rate and the real quality of those leads.