CAC (customer acquisition cost) is the amount a company spends to win one new paying customer. You calculate it by dividing all marketing and sales costs in a chosen period by the number of new customers in the same period.
CAC is the more expensive sibling of CPL. CPL tells you what one contact costs. CAC tells you what one buyer costs.
How do we calculate CAC?
CAC = (marketing costs + sales costs) ÷ number of new customers
The numerator includes:
- ad spend (Google, Meta and other channels),
- tools you need for acquisition and sales (for example a CRM system),
- the share of salaries and other costs of the sales and marketing team that goes into acquiring new customers,
- the cost of external contractors for these tasks.
The denominator counts only new paying customers in the same period, not contacts and not quotes.
What does the calculation look like in euros?
The example is made up and simplified so the logic is visible. Take a company that spends the following in one month:
| Item | Amount |
|---|---|
| Advertising | €3,000 |
| Tools (CRM, tracking, email) | €400 |
| Share of sales and marketing salaries for new customers | €2,600 |
| Total | €6,000 |
In the same month the company won 8 new customers.
CAC = €6,000 ÷ 8 = €750
Each new customer cost the company €750. Only when you compare this figure with the value the customer brings over their lifetime do you know whether acquisition is profitable. How to do that is explained in the article LTV:CAC ratio.
What is the difference between CAC and CPL?
Take the same month. The ads brought 120 contacts (leads), and 8 of them became customers.
| CPL | CAC | |
|---|---|---|
| What it measures | Cost of one contact | Cost of one new customer |
| What it covers | Usually ad spend only | Marketing, sales, tools and team time |
| Denominator | Number of leads acquired | Number of new customers |
| Calculation in the example | €3,000 ÷ 120 = €25 | €6,000 ÷ 8 = €750 |
| What you use it for | Running campaigns week to week | Budget and growth decisions |
The gap between €25 and €750 is not a mistake. It comes from the fact that only 1 in 15 contacts closed (8 out of 120, or about 6.7%), and sales has its own cost. That is why a campaign with an attractive CPL can still bring in customers who cost too much. The basics of the metric are in the glossary entry What is CPL?, and the link between ads and revenue in What is ROAS?.
What are the most common mistakes when calculating CAC?
- Counting only ads. You get a CAC lower than the real one, because sales and tools are left out.
- Mixing periods. A customer brought in by last quarter's campaign is counted in a different period. With a longer sales cycle, use a longer period or cohorts.
- Counting contacts instead of customers. That is CPL, not CAC.
- One CAC for all channels. The average hides the channel that is too expensive and the one that is cheap. If the data allows, calculate CAC per channel.
What does CAC look like in practice?
The public Naitors case reports CPL, not CAC: in one month (April/May 2026) Google Search brought 56 enquiries at a CPL of €14.57 (Naitors case study). CAC would also require data on closed deals and sales costs, which are not part of the public case, so we do not make up a figure.
In lead generation we track CPL to run campaigns and lead quality to judge whether a campaign is working for the business. Once there is enough data (usually after 3–6 months of campaigns), we add the LTV:CAC ratio. How we connect ads, the website and the CRM is described on the lead generation page.
Sources: HubSpot, What is customer acquisition cost (CAC)? (accessed October 2026) · David Skok (For Entrepreneurs), SaaS Metrics: A Guide to Measuring and Improving What Matters (accessed October 2026) · David Skok (For Entrepreneurs), SaaS Metrics 2.0 (accessed October 2026)