CAC: what customer acquisition cost is

CAC (Customer Acquisition Cost) measures how much it costs a company to win a new customer. It's one of the four or five metrics that truly govern the health of a growing business, along with LTV, churn, and margin.

For a creative or marketing team, CAC is the efficiency thermometer: when it rises for no reason, something in the acquisition flow is breaking; when it drops steadily, something is working better than expected and it's worth knowing what.

How to calculate it

Basic formula:

CAC = (total marketing and sales spend) / (new customers in the same period)

If in one quarter you spent 30,000 EUR on advertising, salaries, tools, and an agency, and you won 200 new customers, your CAC is 150 EUR.

It sounds simple. The hard part is deciding what to put in the numerator.

What to include in the calculation

• Paid advertising (paid media across all channels).
• Proportional salaries of the marketing and sales team.
• Tools and software for marketing, CRM, automation.
• Agency and external vendors.
• Content production (creative, video, copy).
• Events and sponsorships.
• Sales commissions.
• Cost of the free trial or samples, if any.

What to leave out

• The cost of the product itself.
• Post-sale support (that's a cost of service, not of acquisition).
• Research and development.
• General operations salaries unrelated to acquisition.

The line isn't always clean (how much of a product marketer's salary counts as CAC?), but the practical rule is: if it's a cost to win the customer, count it; if it's a cost to serve them, don't.

Why CAC on its own says nothing

A CAC of 500 EUR can be excellent or catastrophic — it depends on LTV. That's why the truly useful metric is the LTV/CAC ratio:

• LTV/CAC < 1: you're losing money. Unsustainable.
• LTV/CAC between 1 and 3: marginally profitable.
• LTV/CAC between 3 and 5: a healthy zone, with room to reinvest.
• LTV/CAC > 5: you're probably underinvesting in growth.

On how to calculate and use LTV, read LTV: a fundamental metric.

Segmenting CAC: where the useful information is

Just as with LTV, aggregate CAC hides what matters. The dimensions worth segmenting:

• By channel. How much does a customer cost via SEO vs. paid social vs. outbound sales?
• By customer type. SMB vs. enterprise. They almost always have different CACs.
• By product. If you have several plans, each one has its own CAC.
• By time cohort. The CAC from two years ago may look nothing like today's.

The useful conversation is usually "paid social CAC went up 40% in Q3" — and answering that requires segmenting to find where it broke.

Common mistakes when calculating CAC

• Counting only advertising. It gives you an artificially low CAC and the wrong decisions.
• Including costs that aren't CAC. You inflate the metric and underestimate your real efficiency.
• Calculating it only for new business. Forgetting the cost of winning back returning customers (re-engagement, win-back).
• Not updating the calculation period. If your sales cycle is 6 months, monthly CAC means nothing — use a quarter or a year.
• Not correlating it with quality. Lowering CAC by acquiring customers who churn in 30 days hurts the business even if the metric improves.

Payback period: the complementary metric

The payback period measures how long a customer takes to repay their CAC. Typical SaaS: a payback under 12 months is healthy, under 6 months is excellent. If your payback is 24 months, you need more capital to grow at the same pace as someone with a 6-month payback.

CAC in creative operations

For an agency or in-house team, a substantial part of CAC is creative production: ads, landing pages, content for acquisition. When that production lives in a slow system (briefs by email, endless approvals, assets reinvented for every campaign), CAC rises from operational inefficiency, not from the market.

Centralizing the creative flow in a creative operations platform reduces CAC because it lowers the marginal cost of each campaign: templates are reused, approved assets sit in a library, and approvals take hours instead of days.

At Polimake, the campaign plan lives in Studio, the creative in Studio, and the assets in Media — so that producing the tenth campaign costs less than the first.

Related concepts

• LTV: lifetime value
• ROI: return on investment
• SEM: search engine marketing
• Conversion funnel
• Creative KPIs

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This piece is part of the Polimake glossary and the cluster on creative operations. If you manage growth or a marketing budget, also read Creative KPIs.