What Counts as CAC for a Shopify Store?

Quick answer: Customer acquisition cost (CAC) is what you spend to win new customers in a period, divided by the number of first-time customers in that same period. Every source I read divides the same way. What goes in the top line differs: ad spend always counts, and creative, agency fees, influencer costs, software, staff time and first-order discounts are where sources split. Pick one scope, write it next to the number, and only compare CAC with your own past CAC calculated the same way.

Search for what counts as CAC and you will find guides that use the same three letters for different scopes. Some count ad spend only. Others add agency fees, creative, software, salaries or your welcome discount.

Shopify’s own writing shows it. Two Shopify blog articles on customer acquisition cost, both of which I read for this post, do not list exactly the same costs. One lists discounts and promotional offers as a cost. The other does not say whether discounts count, and says retention spend is out. (Details and dates are in the table below.) If a platform’s own explainers differ, your number can differ from other people’s by far more than a rounding error.

So this post gives you the one formula everyone agrees on, a line-by-line in-or-out table you can copy into a spreadsheet with my reasoning for each line, and an illustrative month where the same store has a CAC of A$40.00, A$57.14 or A$64.50 depending only on scope. Every dollar figure in the worked example is made up to show the arithmetic. None is a benchmark and none comes from a client.

A note on scope. Prism3 sells Shopify SEO, GEO and CRO. We do not run ads or email. This is a measurement guide for whoever owns the store’s numbers, and it works whoever runs your ads. For the wider picture of how paid, organic, conversion and email fit together, see our growth-system guide.

The part everyone agrees on: a numerator and a denominator

Every source I read uses the same shape:

CAC = total acquisition costs in a period ÷ new customers acquired in that period

Stripe’s CAC guide and its CAC payback explainer both state it that way: acquisition costs divided by the number of new customers acquired. Shopify’s July 2024 article on customer acquisition cost does the same, and adds that the figure refers only to first-time customers, not returning ones. Shopify’s July 2026 ecommerce acquisition guide uses total sales and marketing spend divided by new customers acquired. (All as at 30 October 2026.)

Three rules fall out of that before we argue about costs:

1. The denominator is customers, not orders. A returning customer’s order is not an acquisition.
2. Both halves cover the same dates. Spend for October divided by customers for November is not CAC.
3. “New” needs a definition. Shopify’s help centre defines a first-time customer as one who placed their first order with your store, and a returning customer as one whose order history already includes at least one order. It also says customer reports use the whole order history, not only the orders inside the date range you selected, and gives this example: a new customer from November can still display as a repeat customer in a November report if they bought again in December.

That third point matters for your spreadsheet. Shopify’s definition comes from your own order data, so I recommend it as the denominator. Check how a past month’s figure behaves when you pull it again later, and write the pull date next to the number.

Where the sources disagree

Here is what each source says, in my words, as at 30 October 2026. Shopify’s blog articles and Stripe’s guide are educational pages, not rules. Where a page is silent I say so, because silence is not the same as exclusion.

Notice what happens at the edges. Shopify’s 2024 article puts email platforms in the list, and discounts in the list. The 2026 guide splits email in two: email capture tools are in, but post-purchase email flows are out. It does not say whether discounts count. Stripe’s guide is written for SaaS businesses, counts email automation as an acquisition tool, and suggests splitting CAC by channel (paid, organic and outbound) to see where spend is inefficient. It also warns that acquisition cost in one quarter can drive conversions in the next, which is why the period you choose matters.

The next step is worded differently too. Shopify’s CAC payback article divides CAC by average monthly gross profit per customer, and defines gross profit as revenue minus cost of goods sold and other direct costs. Stripe’s payback explainer divides CAC by monthly profit per customer, defined as revenue minus the costs of serving the customer, with support and service costs as examples. Check which costs a payback figure subtracts before you compare two of them.

What Shopify’s own report does

Shopify’s Performance by marketing channel report lists ad spend, return on ad spend (ROAS), cost per acquisition (CPA) and CAC as metrics. Four details from the help pages are worth knowing:

• The page lists CAC and CPA but does not define either one, so check how the numbers behave on your own store rather than assuming a formula.
• Spend-based metrics only appear for channels that report cost data to Shopify, such as a connected ad platform. A dash in a row means no cost data, and the page says a dash is not the same as a zero.
• By default the report shows the last 30 days using a last non-direct click attribution model, and you can change the attribution model and date range.
• The help page says that as of September 2026 this report includes all the traffic that reaches the store, grouped by marketing channel, including rows such as organic and referring traffic that it did not include before, so its totals can be higher than they were. The page does not say how this affects the CAC figure, so if you compare months either side of the change, check the numbers yourself.

A related report, Sales attributed to marketing, only includes sales that can be attributed to trackable marketing efforts, such as campaigns that use UTM parameters. Sales from links without tags can be missing from it.

In short, treat the CAC in Shopify’s report as one version of CAC, built from the cost data Shopify receives. It is a useful starting point, not your full number. (All as at 30 October 2026.)

The scope I recommend, and why

You need a scope you can defend and repeat. Here is the one I recommend for a store at the A$150K to A$1M a year stage, and the reasoning. This is my judgement, not a standard.

I recommend tracking three numbers, labelled, because each answers a different question:

1. Paid CAC (platform-reported): paid media spend divided by the customers the ad platforms say they drove. It answers “is this ad account working on its own terms?”
2. Blended media CAC: paid media spend divided by all first-time customers from Shopify, whichever channel they came from. It answers “what are we paying in media for each new customer, including the ones who arrived from organic, email and word of mouth?”
3. Fully loaded blended CAC: every cost you can honestly tie to winning new customers (media, agency fees, creative, influencers, first-order discounts, acquisition software, your own time and content) divided by all first-time customers. It answers “what does a new customer actually cost the business?”

If you can only keep one, keep number three as the headline and keep number one next to it. Number three is the one that protects you from a nice-looking ad dashboard sitting on top of a store that is quietly losing money per customer. Number one is the one you need to judge a single campaign.

Why blended and not paid only? Organic and direct customers are real customers who arrived at a cost (your content, your SEO work, your brand). A paid-only number cannot see them.

The in-or-out table, line by line

This is the table to copy into your spreadsheet. The “In or out” column is my recommended treatment under the fully loaded scope. The third column says why, and where the choice comes from a source rather than my own rule, I say which.

Two cautions about the table.

It is a scope, not a law. If you decide email platform fees are all retention, fine. What matters is that you decided, wrote it down, and kept it the same.

It is not the same as “what the ad platform shows.” Ad platforms count what they count, over the window they use. Meta’s help centre says its standard attribution settings let advertisers credit conversions to link clicks (counted over 1 or 7 days), to ad impressions (view-through, 1 day) and to other engagements such as non-link clicks and video plays (1 day), and that some accounts may still use earlier versions of these settings. It also says results cannot be compared in the campaign overview table across ad sets using different attribution models, and that if you use external analytics tools you should evaluate performance in those tools. So a CAC calculated from Meta’s reported purchases and a CAC calculated from Shopify’s first-time customers will differ by design. (All as at 30 October 2026.) For the long version of why, see attribution is broken on Shopify, and GA4 versus Shopify Analytics for the same problem inside analytics.

An illustrative spreadsheet: one month, three CACs

Everything below is made up for the arithmetic. It is not a benchmark and it is not a client result. Currency is Australian dollars.

Say a store had 300 first-time customers in the month, according to its Shopify new-versus-returning report, plus a further 120 returning customers who ordered again. Here is the spend, built up one row at a time:

Same store, same month, same 300 customers, and the running CAC moves from A$30.00 to A$64.50 depending on where you stop adding rows. That is why a number quoted without its scope tells you very little.

Now compare three versions, all from the same month:

Read across and you can see three things.

• Paid CAC is higher than blended media CAC here, because the ad platforms report 210 purchases while Shopify shows 300 first-time customers. The two counts cannot be matched one for one: some customers arrive through organic, email, direct or word of mouth, and platform purchases can include returning customers’ orders or overlap each other. (Meta alone is A$9,000 ÷ 140 = A$64.29.) If platform purchases include returning customers, true paid CAC for new customers would be higher still.
• The jump from 40.00 to 64.50 is 61%, and none of it is ad spend. It is the other things that cost money to win a customer.
• Which number is “right” depends on the question. Use paid CAC to judge a campaign, blended media CAC to see what media is costing across the whole store, and fully loaded CAC to judge whether the business is earning from new customers.

Check the number against the first order

A CAC on its own is not a verdict. Put it next to what a first order earns. Continuing the illustration: say the average first order is A$90 before any discount, and product, shipping, packaging and payment costs come to A$51, so the first order contributes A$39 before the discount. The discount is already inside CAC, so we do not subtract it again.

Fully loaded CAC is A$64.50, so the average new customer starts A$25.50 behind. If a repeat order also contributes A$39, that gap closes after about 0.65 repeat orders per new customer (25.50 ÷ 39). That is arithmetic, not a forecast. Whether your customers reorder that often is a question for your own repeat-purchase data. It is the “payback” idea: acquisition cost divided by the profit a customer returns over a period, with the caveat above that Shopify and Stripe word the profit part differently. If you want to build the whole sheet, including repeat purchases, the unit economics spreadsheet walkthrough goes row by row.

Double counting is the trap here. If you start your first-order margin from a figure that already has discounts taken off (check whether your report’s sales figure does), the discount is already deducted there. Put the discount in CAC or in first-order margin, never both. I prefer CAC, because then it travels with the acquisition decision (the offer) and the margin line stays a clean picture of the product.

The denominator, done properly

Most arguments about CAC are about the numerator. The denominator goes wrong just as often.

• Use first-time customers from Shopify, not orders and not platform purchases. Shopify’s New vs returning customers report counts first-time and returning customers over a period, and you can group by day, week, month and so on.
• Remember the lag. Shopify says customer reports might not show all activity from the past 12 hours, with the New vs returning customers report as the exception: opening it gives data current to within seconds. Costs lag more than customers do, because invoices and card statements arrive later. Calculate a month’s CAC after its invoices are in.
• Match the windows. If ads run in October and customers convert across October and November, a single month’s CAC will look different from a rolling 30 or 90-day figure. Choose one and state it.
• Keep wholesale, B2B and marketplace customers out of a DTC number unless you deliberately include their costs too.
• Know what “new” is hiding. A new customer in Shopify might have bought from you before on another channel or under another email. You will never get this perfect. Be consistent and note the limits.

Six steps to set your own definition

1. Write the scope in one sentence. For example: “Fully loaded blended CAC: all acquisition costs in the calendar month divided by first-time customers in that month, in A$, excluding GST.”
2. Open a sheet with these columns: date, cost line, in or out of CAC, amount, and where the figure came from (invoice, card statement, ad platform).
3. Fill every row from the in-or-out table above, including your own time at a stated rate.
4. Pull first-time customers for the same dates from Shopify’s New vs returning customers report.
5. Calculate all three versions in separate, labelled cells, and put the scope sentence next to each number and in any report that quotes it.
6. Compare like with like. This month against last month under the same rules. If you change a rule, recalculate the earlier months first.

Why there is no benchmark here

Plenty of articles quote an average CAC for ecommerce. I have left them out. The example above moves by more than half depending on scope, so a figure that does not state what it counts is not a target. Compare your CAC with last month’s under the same scope and with what a first order contributes.

What the definition changes in practice

Once the scope is fixed, the number tells you where to look.

If paid CAC is high but blended CAC is fine, the ad account may be claiming customers who would have come anyway, or the platform’s attribution is generous. Look at why ROAS can drop before you cut spend.

If blended media CAC is fine but fully loaded CAC is not, the cost is in the rows around the ads: agency fees, creative, discounts, tools and time. That is a conversation about the offer and the operation, not the ad account. What to do first when CAC is high and lifetime value is low covers the order of fixes.

If fully loaded CAC is climbing while ad spend is flat, either something other than media is growing, or fewer visitors are becoming customers. The second is the part you can measure on your own store, and it is plain arithmetic. For paid traffic, the cost of a new customer is roughly the cost of a visit divided by the share of visits that end in a first order. Illustrative numbers: at A$1.20 a visit and 2.0% of visits becoming first-time customers, you pay A$60.00 per customer (1.20 ÷ 0.02). At 2.4% you pay A$50.00 (1.20 ÷ 0.024). Same cost per visit, a different cost per customer, because more visitors bought. That shows the mechanism, not what any change would do for your store.

This is where our work meets your CAC. We do not run ads or email, so we do not touch the numerator’s media lines. We look at the rate visitors become customers after the click, at organic and AI-search visibility (a search visit costs you content and SEO work, not a click, and it can lower blended media CAC when it brings customers the ad account did not), and at tracking, so the paid and email numbers you read can be trusted. Shopify SEO versus Google Ads compares the two routes, and the three numbers Shopify founders watch is a short place to start on which metrics to follow.

Common mistakes

What most often breaks a CAC sheet: dividing by orders instead of first-time customers, mismatched dates, counting the discount twice, leaving out unpaid founder hours, reading a dash as a zero in Shopify’s marketing report, and changing the scope silently, so a “30% improvement” is really a different set of rows.

Not legal or accounting advice: if CAC feeds into reporting to investors, lenders or your accountant, agree the definition with them first.

Key takeaways

• CAC is acquisition costs divided by first-time customers in the same period. Everyone agrees on that. They do not agree on what goes in the cost line.
• Shopify’s own articles differ: one lists discounts and content creation, the other excludes retention spend and does not say whether discounts count. Expect published CAC figures to be unlike each other.
• Track three labelled versions: paid CAC (platform-reported), blended media CAC and fully loaded blended CAC. In the illustrative month the same store reads A$57.14, A$40.00 and A$64.50.
• Use first-time customers from Shopify’s new-versus-returning customers report, not orders or platform-reported purchases.
• Count a first-order discount once, in CAC or in first-order margin, not both.
• Do not use a published benchmark unless it states exactly what it counts. Compare your CAC with your own history under the same scope and with what a first order contributes.
• Write the scope next to the number, every time.

FAQs

What is included in customer acquisition cost for ecommerce?

Ad spend always. Beyond that, sources differ. Shopify’s articles variously include creative and content, agency and contractor fees, influencer fees, acquisition software, a share of acquisition staff time and discounts, and exclude retention spend. For a fully loaded view, I count everything tied to winning new customers and leave out fulfilment, returns and service. Whatever you choose, state the scope.

Does CAC include organic traffic?

The customers who arrive organically belong in the denominator of a blended CAC, and the cost of earning them (content, SEO work, tools) belongs in the numerator of a fully loaded CAC. Paid-only CAC ignores both. Shopify’s 2024 article does not exclude organic. Its only mention is a quoted contributor saying organic leads tend to be more cost-effective than paid ones.

Should CAC include first-order discounts?

I count them, once. Shopify’s 2024 article lists discounts and promotional offers as a cost, and its 2026 guide does not say whether they count, so the sources do not line up. The discount is a price paid to win the customer. If you count it in CAC, do not also deduct it when you work out first-order margin.

Does CAC include email marketing?

Split it. Shopify’s two articles differ here. My rule is to count the part of email and SMS spend used to capture new subscribers and send the first welcome message, and to leave out flows aimed at existing customers (the 2026 guide excludes retention spend). If you cannot split it, leave it out of both and write that down. We do not run email, so this is a measurement rule, not a service we sell.

What is the difference between CAC and CPA?

Shopify’s marketing report lists both as separate metrics, and the help page I read does not define either one. Shopify’s 2024 blog article says CAC counts only first-time customers. Check whether a CPA figure counts every conversion or only first-time customers before you compare it with CAC.

Does Shopify calculate CAC for me?

Shopify’s Performance by marketing channel report shows a CAC metric, but only for channels that report cost data to Shopify, and the help page does not give a formula for it. It defaults to the last 30 days and a last non-direct click model. It is a starting point. A fully loaded CAC needs your own sheet.

What is a good CAC for a Shopify store?

There is no single good number. A CAC is good if a first order plus the repeat orders you can expect pays it back inside the time your cash can wait. Compare it with your own history under the same scope and with first-order contribution, not with a published average.

Keep reading

• What to do first when CAC is high and lifetime value is low
• The Shopify unit economics spreadsheet, step by step
• The Shopify growth system: paid, organic, CRO and email

Is your cost per customer rising while orders stay flat?

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