CAC

Companies spend money to acquire new customers: on advertising, on salespeople, on sign-up discounts. CAC is the abbreviation for Customer Acquisition Cost. It refers to the amount a company spends on average to gain a single new paying customer. To calculate it, you add up all advertising and sales expenses over a given period and divide them by the number of new customers acquired in that period. An example: A provider spends 200,000 euros on advertising and sales in one month and gains 1,000 new customers as a result. Its CAC is therefore 200 euros per customer. Whether that is a lot or a little cannot be determined from the number alone.

Why 200 euros per customer can be cheap or ruinous

CAC only becomes meaningful once you compare it to what a customer actually brings in. This counterpart figure is called Customer Lifetime Value, or LTV for short: the total profit a customer generates over the duration of their relationship with the company. If a customer pays 30 euros a month for two years, they bring in far more than 200 euros. If they cancel after three months, acquiring them was a losing proposition.

In the software industry, a rule of thumb has held for years: lifetime value should be at least three times as high as CAC. A second widely used metric is the payback period. It indicates after how many months a customer has earned back their own acquisition cost. Under twelve months is considered healthy; significantly above that becomes dangerous for young companies.

This is why CAC is one of the most important figures for investors. A fast-growing start-up can show impressive user numbers and still be a bad business. If every new customer costs more than they will ever bring in, growth merely speeds up the path to losses. This was exactly the pattern seen with many delivery services that bought customers with vouchers and never became profitable.

What belongs in the calculation — and what tends to get left out

The numerator of the formula should include all costs that serve customer acquisition. That means ads on Google and Instagram, salaries in marketing and sales, commissions, trade show appearances, and promotional giveaways. The denominator is the number of new customers acquired in the same period. It’s important that both figures correspond to each other.

This is exactly where numbers are often massaged. Some companies count only pure ad spend and leave out salespeople’s salaries. Others also count customers who came on their own, without any advertising involved. Both artificially lower CAC. Experts therefore often look at what’s called blended CAC, which truly includes all channels, and compare it to the CAC of individual advertising channels.

Another effect makes matters more confusing: CAC almost always rises with scale. The first customers are often enthusiastic early adopters and cheap to acquire. The more a market has already been tapped, the more expensive each additional customer becomes. A low CAC from a company’s founding year therefore says little about the future.

CAC in quarterly reports and the AI boom

Anyone reading business news encounters the term mainly in connection with subscription companies. Streaming services, software providers, neobanks, and fitness apps regularly report what a new subscriber costs. If CAC rises while the churn rate rises as well, markets tend to react sharply. Analysts almost always ask about this figure on earnings calls.

In the context of artificial intelligence, CAC comes up from two angles. On one hand, AI tools promise to lower it: chatbots take over sales conversations, and ads are automatically tailored to individual target groups. On the other hand, AI providers themselves have a CAC problem. They compete for the same corporate customers and must offer their tools for free for a long time just to get anyone to try them at all.

A common misconception is treating CAC as a fixed trait of a company. In reality, it’s an average across very different customers and channels. An enterprise customer might cost months of sales work, while an individual consumer might cost just a few cents in advertising. Meaningful conclusions only emerge once these groups are looked at separately.