CAC (Customer Acquisition Cost)

Definition

CAC is the total cost to acquire one new paying customer, including all marketing and sales expenses divided by the number of new customers gained in that period. If you spend $4,000 in a month on ads, software, and your time following up, and you close 10 new customers, your CAC is $400. CAC is the number that tells you whether growth is sustainable. A business where CAC is lower than the value of a customer is a business that can scale. A business where CAC exceeds what customers are worth is bleeding money with every sale.

How It Works

To calculate CAC, total all costs tied to customer acquisition: ad spend, agency or contractor fees, CRM or automation software costs, and a realistic estimate of staff time spent on sales. Divide by the number of new customers closed in the same period. Some businesses use a simplified version that only includes direct ad spend. Others include every dollar that touches lead generation and conversion. The more complete version is harder to track but more accurate for business decisions.

CAC is most useful when tracked over time and compared against LTV. A rising CAC is a warning sign: either competition for paid traffic is increasing, conversion rates are slipping, or your sales process is getting less efficient. A CAC that is dropping usually means better targeting, better landing pages, or faster follow-up.

Why It Matters

For small businesses, CAC sets a ceiling on what you can afford to spend per lead. If your average customer spends $800 with you, a $600 CAC leaves very little room. If that same customer refers two others over the next year, the picture changes. Knowing your CAC forces you to look honestly at every part of the acquisition process: which channels are too expensive, where leads drop off, and whether the follow-up process is converting at the rate it should be. Speed-to-lead is a direct driver of CAC. Leads followed up within five minutes convert at significantly higher rates than leads that wait hours, which means faster response lowers your effective CAC.

Example

A landscaping company spends $1,500 per month on Google Ads and $200 per month on a CRM tool. The owner spends about 5 hours per week following up with leads at an imputed cost of roughly $500 per month. Total acquisition investment: $2,200. In that month, they close 11 new maintenance contracts. CAC: $200 per customer. Average contract value: $1,800 per year. CAC is well inside the acceptable range. If the owner cut response time from 6 hours to 15 minutes using automated follow-up, the close rate on leads would increase and CAC would drop further.

Related Terms

LTV, ROAS, Conversion Rate, PPC, CPC

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