Customer Acquisition Cost (CAC)
Customer Acquisition Cost (CAC) is the total cost of acquiring one new customer, including marketing, sales, and tools.
What it means
CAC tells you what you're spending to bring in each new customer. For a SaaS product, it includes ad spend, content marketing costs, sales salaries, tooling, and any other resources used to acquire customers. Divide your total acquisition spend by the number of new customers in that period and you get CAC.
The number on its own is meaningless. What matters is CAC compared to LTV (lifetime value). If you spend $100 to acquire a customer who pays you $1,000 over their lifetime, that's a great deal. If you spend $100 to acquire a customer who pays $50, you're losing money.
For indie products, CAC is often near zero (organic content, word of mouth). That's a huge advantage but it's also fragile. If your only acquisition channel is one viral tweet, CAC is technically zero but unsustainable.
Why it matters
CAC determines whether your business scales profitably. Low CAC means you can grow without raising money or burning cash. High CAC means every new customer costs you, and you have to make it back through retention. Knowing your CAC is the first step in deciding whether to spend on ads, content, or sales.
How to calculate customer acquisition cost (cac)
CAC = Total Acquisition Spend / New Customers
Divide total acquisition spend by the number of new customers acquired in the same period.
Example with real numbers
Concrete example showing how this metric works in practice.
Scenario
Last month you spent $2,000 on ads, $500 on content, and $1,500 on sales tools. You acquired 40 new customers.
Calculation
($2,000 + $500 + $1,500) / 40 = $100
What it means
Your CAC is $100. If your average customer pays $30/month and stays 6 months, your LTV is $180. That's a 1.8x LTV:CAC ratio, which is below the 3x rule of thumb but workable while you optimize.
What's a good number?
Typical benchmarks. Always compare against your own historical data first, industry averages second.
LTV:CAC below 1x (losing money)
LTV:CAC 1x to 3x
LTV:CAC 3x to 5x
LTV:CAC above 5x
These are LTV:CAC ratios, which matter more than CAC alone. The 3x rule says LTV should be at least 3 times CAC for a healthy SaaS business. Indie products with organic acquisition often see ratios well above 10x.
Common mistakes
Things people get wrong when measuring customer acquisition cost (cac).
Mistake 01
Forgetting to include time and tooling costs. CAC is more than just ad spend.
Mistake 02
Mixing organic and paid CAC together. Track them separately to understand each channel's economics.
Mistake 03
Calculating CAC on a tiny sample. With 5 new customers in a month, the number is too noisy to trust.
Mistake 04
Optimizing CAC down without checking LTV. Cheap customers who churn fast hurt more than expensive ones who stay.
How to track it
List every acquisition cost (ads, content, sales, tools) for a period. Divide by new customers in that period. Track monthly. The most useful view is CAC by channel, since each channel has very different economics.
Related concepts
Other terms worth learning if you're studying this one.
Common questions about customer acquisition cost (cac)
It depends on LTV. A good rule of thumb: CAC should be one-third or less of LTV. So if your customer pays you $300 over their lifetime, your CAC should be $100 or less.
Add up everything you spent acquiring customers in a period (ads, content, sales, tools), then divide by the number of new customers in that period. The result is your average CAC.
It's how many times more revenue you get from a customer than what it cost to acquire them. A 3x ratio means you make $3 for every $1 spent acquiring. Below 1x means you're losing money on each customer.
Improve conversion rate (more customers from same spend), shift to lower-cost channels (organic content, referrals), or improve targeting so you reach more qualified visitors. Conversion rate improvements compound the fastest.