How to calculate customer acquisition cost (and know if it paid off)

To calculate customer acquisition cost (CAC), add up everything you spent on marketing and sales in a period and divide it by the number of first-time customers you won in that same period. A brand that spends $60,000 in a quarter and gets 1,200 new customers has a CAC of $50.

That number on its own doesn't tell you much. A $50 CAC is cheap for a brand selling $400 jackets and painful for one selling $15 candles, and whether it's worth paying depends on what happens after the first order. This guide walks through the calculation in retail terms, then shows how to check it against lifetime value and payback so you know whether your acquisition spend is working.

What is customer acquisition cost?

Customer acquisition cost is the average amount you spend to win one new customer. For an ecommerce or retail brand, a new customer is someone placing their first order with you, and CAC covers the money it took to get them there: ads, agencies, tools, creatives, promotions, and the people working on acquisition.

CAC is an average across a period, usually a month or a quarter. Some customers cost you almost nothing because a friend sent them, and some took six retargeting ads and a welcome discount. CAC rolls them together so you can compare it with what a customer is worth over time.

CAC vs. CPA

Cost per acquisition (CPA) and CAC get used interchangeably, but they measure different things. CPA usually comes from ad platforms: it divides campaign or channel spend by the purchases or conversions the campaign drove. It's useful for judging one campaign against another.

CAC is broader. It counts every acquisition cost, including salaries, tools, and discounts, and it only counts first-time buyers. That's why benchmark numbers can look so far apart. Triple Whale's 2026 ecommerce benchmarks put the median paid-ads CPA across its brands at $23.20 from August 2025 to July 2026, with individual verticals ranging from $26.65 in Baby to $44.12 in Electronics (Apparel and Accessories sat at $31.44). Those are ad spend figures, so a brand’s fully loaded CAC will be above its CPA.

The CAC formula

CAC = (marketing costs + sales costs) ÷ new customers acquired

Both sides of the formula need to cover the same period. If your costs are for Q3, your customer count has to be Q3's first-time buyers too.

What to include

Count anything you spent to bring in someone who hadn't bought from you before:

• Paid media: search, social, display, shopping ads, podcast, and streaming TV ads

• Acquisition salaries and commissions, including the share of your marketing team's time spent on winning new customers

• Agency, freelancer, and creative production fees

• Marketing tools and software used for acquisition

• Content, influencer, and affiliate costs

• Promotions and first-order discounts, because a 20% welcome code is money you gave up to win the sale

First-order discounts are the easiest line to miss. If 1,000 new customers each use a $15 welcome code, that's $15,000 of acquisition cost that never shows up in your ad accounts.

What to leave out

Leave out the cost of serving customers once they've bought. Customer service, shipping, fulfillment, and returns processing belong in your cost-to-serve. Folding them into CAC buries the very costs you'd want to manage on their own, and it makes your acquisition team look worse for things it doesn't control.

Retention spend stays out, too. Loyalty programs, win-back emails, and replenishment reminders aimed at people who already buy from you are about keeping customers, so they belong on the lifetime value side of the ledger.

How to calculate CAC step by step

Here's the full calculation for a fictional apparel brand over one quarter.

Step 1: Pick the period. Use a full quarter. A single month can swing hard around a sale or a product drop, and a quarter smooths that out.

Step 2: Add up marketing costs. The brand spent $30,000 on paid social and search, $6,000 on an agency, $4,000 on creatives and content, $2,500 on marketing tools, and gave away $5,500 in first-order discounts. That's $48,000.

Step 3: Add up sales costs. Most retail brands have no sales team in the B2B sense, but they still pay people to win new customers. The share of its growth team's salaries spent on acquisition, plus commissions from its partnership program, totals $12,000.

Step 4: Count only first-time customers. The store took 3,000 orders in the quarter. Of those, 1,800 came from people who'd bought before, so the brand acquired 1,200 new customers.

Step 5: Divide. $60,000 ÷ 1,200 = $50 CAC.

If the brand had divided by all 3,000 orders, it would've reported a $20 CAC and assumed its acquisition was far cheaper than it is. That's the most common way CAC goes wrong, and we'll come back to it.

Blended CAC vs. paid CAC

The $50 above is the blended CAC: total acquisition spend divided by all new customers, including those who found the brand through organic search, word of mouth, or a friend's Instagram post. Blended CAC tells you what growth costs the business overall.

Paid CAC narrows both sides to paid channels. Say the brand's analytics attribute 480 of the 1,200 new customers to paid ads. The spend behind those ads was $30,000 in media plus the $6,000 agency fee, so the paid CAC is $36,000 ÷ 480 = $75.

Paid CAC is almost always higher than blended, because organic customers pull the blended average down. Use paid CAC when you're deciding whether a channel deserves more budget, and blended CAC when you're judging whether the business can afford its growth. If blended CAC looks healthy only because word of mouth is carrying it, you'll find out the hard way when you try to scale paid.

How to tell if your CAC is good

There's no single good CAC. A number only means something next to what a customer earns you, and for a retailer, that comes down to how many times they order and how much you keep from each order.

Outside benchmarks can give you a rough sense of range. First Page Sage's B2C CAC report, based on 103 of the agency's own clients from 2021 to 2025, puts ecommerce CAC at $64 for organic channels and $68 for paid. It's a small sample from one agency's client list, so treat it as a sanity check. Your own LTV:CAC ratio and payback will tell you far more.

LTV:CAC ratio

The LTV:CAC ratio divides a customer's lifetime value by what it cost to acquire them. Back to the apparel brand: its average order is $80, and its gross margin is 50%, so each order generates $40 in gross profit. The average customer places three orders.

• Revenue LTV: 3 × $80 = $240, so LTV:CAC is $240 ÷ $50 = 4.8:1

• Profit LTV: 3 × $40 = $120, so LTV:CAC is $120 ÷ $50 = 2.4:1

Same customer, same CAC, and the ratio halves depending on which LTV you use. That matters because the most quoted target, 3:1, comes from SaaS. David Skok's guideline for software companies was an LTV more than three times CAC, and he based it on a simple revenue LTV for businesses with gross margins of 80% or higher. At 80% margins, revenue and profit LTV are close. At 50%, profit LTV is half of revenue LTV.

Treat 3:1 as a rule of thumb. If you calculate LTV from revenue, aim well above it. If you calculate from gross profit, 3:1 is a reasonable floor, and this brand's 2.4:1 says it's paying a little too much for customers or not getting enough orders out of them. Not sure what your lifetime value is? Our guide to customer lifetime value covers the calculation, or you can run your numbers through the CLV calculator.

CAC payback in orders

Payback tells you how long it takes to earn back what you spent to win a customer. SaaS companies measure it in months because revenue arrives as a monthly subscription. Skok's guideline was under 12 months, though he's since said longer can be fine. Retail revenue arrives one order at a time, so it makes more sense to count orders.

CAC payback (orders) = CAC ÷ gross profit per order

For the apparel brand, that's $50 ÷ $40 = 1.25 orders. The first order covers $40 of the $50, and the brand doesn't break even on a new customer until they come back for a second.

A payback of 0.8 orders means you're profitable on the first purchase and every repeat order is upside. A payback of 1.25 means the second order is where the money is, so the share of new customers who ever place one matters more than almost anything else you track. A payback of 2.5 means you're betting on a third order, and you'd better know your repeat rate supports that bet.

If you want a time frame too, pair it with your reorder interval. If customers typically come back about 60 days after their first purchase, a 1.25-order payback means you're waiting roughly two months to get your money back from the ones who return.

Common CAC mistakes

Counting repeat buyers as new customers

Dividing by total orders, or by everyone who bought in the period, makes CAC look much cheaper than it is. In the example, that error turned a $50 CAC into $20. Paid campaigns are especially prone to this, because retargeting and branded search ads pick up a lot of people who were going to buy again anyway. Pull new-customer counts from your ecommerce platform's first-order data, since ad platforms count returning buyers as conversions too.

Mismatched time periods

Divide a full year of ad spend by one quarter's new customers and your CAC looks four times worse than it is. The apparel brand would see $240,000 ÷ 1,200 = $200. The reverse mistake, a quarter of spend over a year of customers, makes it look four times better. Lock both sides to the same dates. If you run big campaigns that pay off weeks later, like a holiday push in November that converts in December, a quarterly window catches most of that lag.

Ignoring returns and refunds

A customer who returns their only order and never comes back cost you the full acquisition spend and earned you nothing. If 120 of the brand's 1,200 new customers returned their first order for a full refund and didn't buy again, the brand kept 1,080 of the customers it paid for, and its CAC is $60,000 ÷ 1,080 = $55.56. Apparel and footwear brands with high return rates should calculate CAC on kept first orders, or at least track both versions.

How to make your CAC pay off faster

Most advice on lowering CAC is about spending less: cheaper channels, tighter targeting, smaller discounts. That works up to a point, and then it starts costing you growth. The other lever is getting more back from the customers you've already paid for. Your CAC stays $50, but each customer earns more, so the ratio improves and payback shortens. If you're feeling the pressure of rising ad costs, our post on customer retention strategies when acquisition costs spike goes deeper on that side.

Run the apparel brand's numbers with one more order per customer. Lifetime gross profit goes from $120 to $160, and LTV:CAC moves from 2.4:1 to 3.2:1 without a dollar of extra acquisition spend.

A lot of those extra orders are won or lost after the first purchase. A shopper whose package is late, whose size is wrong, or whose subscription isn't working for them will either get a fast, personal answer or start looking elsewhere. Every one of those conversations is a chance to protect the money you spent to win them. The metrics that predict customer lifetime value are worth watching here, especially repeat purchase rate and time to second order, along with the customer retention metrics your service team already tracks.

Ollie, the fresh dog food brand, puts this into practice. When subscription members reach out to cancel and Ollie's CX team handles the conversation, it keeps 45% of them. Each of those members is a customer Ollie doesn't have to pay to win back.

Gladly's AI handles a lot of those post-purchase questions about orders, returns, and products, and when a person needs to step in, your team sees the customer's full history. For more on how service shows up in revenue, see the ROI of AI in commerce.

Run the numbers before you change the budget

When CAC climbs, the usual first move is to cut spend. Run the full picture first. You need four numbers you probably already have: last quarter's acquisition spend, how many first-time buyers kept their first order, your gross profit per order, and how many orders the average customer places.

Those give you CAC, LTV:CAC on profit, and payback in orders, and the payback number tells you what to do next. Under one order, acquisition pays for itself on the first sale and you have room to spend more. Between one and two, your repeat rate decides whether the spend works, so the second order is where to focus. Above two, check that your repeat data supports that many orders before you scale, because you're counting on purchases from customers who haven't come back yet.