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Customer Acquisition Cost Calculator: Find Your True CAC

Enter four numbers and get your CAC, LTV:CAC ratio and payback period instantly, with the benchmarks that tell you if your growth is healthy.

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Customer acquisition cost (CAC)
$400
LTV:CAC ratio
6.0:1
CAC payback
5.7 months
Margin-adjusted LTV:CAC
4.2:1

Healthy: every $1 of acquisition spend returns $6.00 in lifetime value.

How your CAC compares

The bar shows your margin-adjusted LTV:CAC against the benchmarks. The 1:1 line is where you break even, 3:1 is healthy, 5:1 and up means you can usually afford to grow faster.

1:1 break-even3:1 healthy5:1 efficientYour ratio
Gross profit per customer
$0
Monthly gross profit per customer
$0
Lifetime value per customer
$0
Payback verdict
-

Built by Rankite, the SEO team behind Swordfish AI's +400% revenue and Zluri's +45% organic growth. See the case studies

Customer acquisition cost, or CAC, is what you pay on average to win one new customer. It is one of the few numbers that tells you whether your growth is profitable or quietly burning cash. The calculator above turns your own spend and customer counts into CAC, an LTV:CAC ratio and a payback period, so you can judge the health of your acquisition in seconds.

How to calculate customer acquisition cost

The formula is straightforward: total sales and marketing spend for a period, divided by the number of new customers you acquired in that same period. Include everything that goes into winning customers, not just media. That means ad spend, agency or freelancer fees, the salaries of the people running acquisition, and the tools they use.

Here is a worked example. Say you spent $20,000 across a quarter and acquired 50 new customers. Your CAC is $20,000 divided by 50, which is $400 per customer. If each customer is worth $2,400 over their lifetime, your raw LTV:CAC ratio is 6:1. Apply a 70% gross margin and the real return is $1,680 of gross profit per customer, which is an honest 4.2:1.

What is a good CAC and LTV:CAC ratio?

There is no universal good CAC in dollars, because it depends entirely on what a customer is worth to you. That is why the ratio matters more than the raw number. The widely cited benchmark is 3:1, meaning every dollar you spend on acquisition returns three dollars in lifetime value. Below 1:1 you are losing money on every customer. Above 5:1 you may be underinvesting and leaving growth on the table. On payback, common SaaS benchmarks treat under 12 months as good and under 6 months as excellent, because a faster payback frees cash to acquire the next customer sooner.

How to lower your CAC with SEO

Paid channels charge you for every single click, so as you try to scale, your CAC tends to stay flat or climb. SEO works differently. The content and authority you build keep producing customers after the work is done, which means cost per customer falls over time rather than rising. As organic traffic compounds, a growing share of your customers arrive without any per-click cost, and your blended CAC drops with them. If you want to see how much organic search could pull your acquisition cost down, Rankite can model it against your real rankings and competitors. Book a call and we will walk through the numbers with you.

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FAQ

CAC Calculator: questions, answered

How do you calculate customer acquisition cost?
Divide your total sales and marketing spend for a period by the number of new customers you acquired in that same period. If you spent $20,000 and won 50 customers, your CAC is $400. Include ad spend, salaries, agency fees and tools so the number reflects the true cost to acquire a customer, not just media cost.
What is a good LTV:CAC ratio?
A 3:1 ratio is the widely cited healthy benchmark, meaning each customer returns three times what you paid to acquire them. Below 1:1 you lose money on every customer. Above 5:1 often signals you are underinvesting in growth and could acquire faster. Most efficient SaaS businesses target the 3:1 to 5:1 range.
What is CAC payback period?
CAC payback is the number of months it takes for the gross profit from a customer to cover the cost you spent acquiring them. Under 12 months is considered good for most SaaS and subscription businesses, and under 6 months is excellent. Longer paybacks tie up cash and slow how fast you can reinvest in growth.
Why should I use gross margin in CAC math?
Revenue is not profit. A customer worth $2,400 in lifetime revenue at a 70% gross margin only returns $1,680 in actual gross profit. Payback and ratio decisions should be based on the margin-adjusted value, because that is the cash actually available to cover acquisition costs and fund the next customer.
How does SEO lower customer acquisition cost?
Paid channels charge you for every click, so CAC stays flat or rises as you scale. SEO builds an asset: the content and authority you create keep producing customers after the work is done, so cost per customer falls over time. As organic traffic compounds, blended CAC drops because a growing share of customers arrive without per-click cost.

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