CAC Calculator (Customer Acquisition Cost)

How do you use the CAC calculator?

Enter your acquisition spend and the number of new customers for the same period. The calculator shows CAC straight away.

1. Pick a period, such as a month or a quarter.
2. Add up acquisition spend for that period. Start with ad spend; add creative, agency and tool costs if you want a fully loaded CAC.
3. Count new customers: people who bought for the first time in the period. Leave out repeat buyers.
4. Enter both numbers above, and copy the page link to share the result. Only the numbers are stored in it.

What is the CAC formula?

CAC is acquisition spend divided by new customers, both from the same period. Shopify's guide describes it the same way: add up acquisition costs for a period, then divide by the new customers who made purchases in that period.

CAC = acquisition spend ÷ new customers

The numerator is a choice. Ad spend alone gives paid CAC. Ad spend plus creative production, agency fees and tools gives a fuller figure. Use the same choice every time, or the trend means nothing.

Worked example

Enter these numbers in the calculator above (example numbers, in any currency):

The tool shows the same result:

Compare this with CPA. Say the same 2,500 brought 50 purchases, 40 from new customers and 10 from people who had bought before. CPA is 2,500 ÷ 50 = 50, while CAC is 62.50. The CPA calculator gives the first figure; this page gives the second.

What should a fully loaded CAC include?

A fully loaded CAC adds every cost of winning customers, not only media. Decide which lines you include and keep them the same from month to month.

Paid CAC is easier to compare week to week. Fully loaded CAC is the honest number for deciding whether a channel pays.

How do you compare CAC with lifetime value?

CAC is only high or low relative to what a customer is worth. Put it next to lifetime profit per customer from the LTV calculator.

In the LTV calculator's example, a customer orders 3 times a year at 60 for 2 years, with a 40 percent margin: 144 in lifetime profit. Against a CAC of 62.50, each new customer returns more than twice their acquisition cost in margin over two years. Against first-order margin alone (24), the same CAC loses money until later orders come in.

That gap is the cash-flow question every ecommerce brand has to answer: the CAC is paid now, and most of the margin arrives later. Shopify's lifetime value guide covers the LTV side of the same comparison.

What are the limits of this calculator?

The calculator divides spend by customers. The hard part is deciding what goes into each number.

• Counting new customers. Your store's first-time buyer count and the ad platform's attributed purchases are different numbers. Use the store count for CAC.
• Timing. Spend in one month can bring customers the next month. Longer periods smooth this out.
• Paid versus blended. Dividing ad spend by all new customers (including ones from search, word of mouth or email) gives a lower, blended CAC. Label which one you report.
• No benchmarks. CAC depends on price, category and channel, so the tool shows no "good" or "bad" verdict.

Related tools and glossary entries

See the CAC glossary entry, with links to LTV and CPA. The contribution margin calculator gives the margin you need for lifetime profit, and the ad metrics calculator shows the per-order ratios from one form. All free tools are on the tools page.

If you want more ad creative to bring CAC down, see how Anglr works for brands.