Customer acquisition cost is what it costs, on average, to win one new customer. On its own it is just a cost line. Set against the gross profit a customer brings, it answers a sharper question: is growth paying for itself, and how quickly?
This guide walks through the customer acquisition cost formula used by the free ORVX CAC Calculator, how it turns CAC into payback, a worked example and the limits of the method.
Every example and amount on this page is illustrative. It shows the method and is not a benchmark, a quote or advice.
The formula
CAC = (marketing spend + other acquisition costs) / new customers
Two choices decide whether the number is useful. First, the period: spend and new customers must come from the same window, usually a month or a quarter. Second, what counts as acquisition cost. Ad spend is the minimum. Agency fees, creator payments and first-order discounts are acquisition costs too, and the calculator has a separate field for them so you can see the difference they make.
From CAC to payback
If you also enter average order value and gross margin, the calculator works out:
- Gross profit per order: order value x gross margin.
- Orders to pay back CAC: CAC divided by gross profit per order.
- First order profit after CAC: gross profit per order minus CAC.
- 12-month gross profit per customer: gross profit per order x orders per customer per year, if you enter a frequency.
- 12-month value to CAC: that 12-month figure divided by CAC.
Worked example
As an illustration only, suppose a store spent $12,000 on ads last quarter and $1,500 on other acquisition costs, and won 300 new customers. The average order is $68, the gross margin is 55%, and customers order about 1.8 times a year.
| Result | Value |
|---|---|
| CAC ($13,500 / 300) | $45.00 |
| Gross profit per order ($68 x 55%) | $37.40 |
| Orders to pay back CAC ($45 / $37.40) | 1.2 |
| First order profit after CAC | -$7.60 |
| 12-month gross profit per customer ($37.40 x 1.8) | $67.32 |
| 12-month value to CAC ($67.32 / $45) | 1.5 |
The first order in this example loses $7.60 once acquisition is counted, so the store needs the second order to come back into profit. Over twelve months each customer brings $67.32 of gross profit against $45 of CAC, a ratio of 1.5. Whether that is acceptable depends on cash: the store pays the $45 now and recovers it over months.
If the same store counted only ad spend, CAC would be $12,000 / 300 = $40. That looks better, and it is the reason the second field exists: the cost of a creator post is as real as the cost of a click.
How to use it
- Pick a period long enough to smooth out daily noise, and use the same period for spend and customers.
- Count only new customers. Your store's customer report can split first-time buyers from returning ones.
- Use gross margin after product cost, not after shipping and fees, so the result matches the formula. For a stricter view, enter the margin after shipping too.
- Run it per channel if you can. A channel with a high CAC can still be worth it if its customers order more often.
- Compare the orders-to-payback figure with how often customers actually come back. If payback needs three orders and most customers buy once, the channel is losing money.
To check a single campaign against its costs, the Break-Even ROAS Calculator is the faster tool. To see how competitors position their products and prices, try the Competitor Store Analyzer.
Common mistakes
- Dividing by all customers. Returning customers did not cost acquisition spend, so they lower CAC artificially.
- Mismatched periods. Spend from one month and customers from another give a number that means nothing.
- Using revenue instead of gross profit for payback. A customer who spends $68 does not give you $68 to recover CAC with.
- Treating a 12-month ratio as lifetime value. Order frequency is an assumption here. Real lifetime value needs real repeat history.
The trade-off between acquisition cost and order profit is covered in more depth in CAC vs Profit per Order.
Reading the number over time
A single CAC figure is less useful than its direction. Work it out the same way every month and watch three things together: CAC, gross profit per order and orders per customer. CAC rising while gross profit per order holds steady means each new customer is getting more expensive to win. CAC holding steady while repeat orders fall means the same spend is buying less value. Neither shows up if you only look at one month.
Limits
The calculator uses averages. It cannot tell which customers came from which channel, how attribution was decided, or whether a customer would have bought without the ad. Its 12-month view assumes the frequency you enter, rather than measuring it. Nothing you type leaves your browser.
Measuring it from real customers
A one-off CAC is an estimate. ORVX Core lists every customer with their orders and what they are worth to the business, and counts ad spend in net profit, using your own Shopify data instead of typed averages.
The $1.9M Commerce Initiative gives 10,000 eligible Shopify stores 12 months of ORVX Core free, with no credit card. After that, Core is the standard $19 per month or $190 per year if you choose to keep it. The other calculators and store checks are in the ORVX tools hub.
Frequently asked questions
What counts as marketing spend in CAC?
Everything you spent to win new customers in the period: ad spend, and if you want a fuller picture, agency fees, influencer payments and the cost of discounts given only to first orders.
Should I count returning customers?
No. CAC divides by new customers only. Including repeat buyers lowers the number and hides what new customers really cost.
What is a healthy 12-month value to CAC ratio?
It depends on your margins and cash position. Above 1 means a customer's first year of gross profit covers what they cost to win. Below 1 means you are relying on later years, or losing money.
Is this a lifetime value calculation?
No. It is a simple 12-month view based on the order frequency you enter. Lifetime value needs real repeat-purchase history, not an assumption.
Is my data stored?
No. The calculator runs in your browser and sends nothing.
Sources
- The $1.9M Commerce Initiative: terms and FAQ (ORVX, checked 26 October 2026)