How to use CAC Calculation
A practical walkthrough of how customer acquisition cost is actually computed — what counts as spend, blended versus channel CAC, and the reporting traps to avoid.
CAC Calculation
CAC calculation divides total acquisition spend by new customers acquired in the same window to produce customer acquisition cost.
Customer acquisition cost (CAC) is calculated by taking everything you spent to acquire customers in a given period and dividing it by the number of new customers you gained in that same period. The formula is simple; the judgement calls are not. What counts as acquisition spend, whether you include organic traffic, and how you attribute multi-touch journeys all change the number materially.
Most stores report at least two versions: a blended CAC across all spend and channels, and a paid or channel-attributed CAC that isolates marketing efficiency. Both are useful for different decisions, and confusing them is the most common reason finance and marketing disagree about whether growth is profitable.
On the surface the CAC formula looks like a one-line calculation: spend divided by new customers. In practice the inputs to that division are where every store gets it wrong, because both the numerator and the denominator are squishier than they appear.
This guide walks through the calculation the way a CFO would scrutinise it: what to include in spend, how to handle organic and branded traffic, when to use blended versus channel-level CAC, and the specific pitfalls that quietly inflate or deflate the number you report to the board.
What counts as acquisition spend
The numerator of CAC is total acquisition spend in the period. At minimum this includes paid media (Meta, Google, TikTok, affiliate payouts), agency or freelancer fees tied to acquisition campaigns, and any creative production costs you can reasonably attribute to acquiring new customers rather than retaining existing ones.
More rigorous calculations also load in fully-burdened marketing salaries, marketing software (your ad management, attribution, and analytics stack), influencer fees, and a share of content production. The rule of thumb: if the cost would disappear when you stopped acquiring new customers, it belongs in CAC.
What does not belong: brand campaigns measured on awareness rather than response, retention-focused email and SMS spend, post-purchase loyalty programs, and customer support tooling. Mixing these in drags CAC upward and makes paid channels look worse than they are.
The discount trap
First-order discounts (welcome codes, 15% off your first purchase) are acquisition costs in everything but name. If your CAC excludes the €12 you gave away on a €40 first order, you are reporting a number that is structurally too low. Add discount-on-first-order to your acquisition spend, or net it out of revenue before computing margin.
Blended CAC vs channel-attributed CAC
Blended CAC divides all acquisition spend by all new customers in the period — including those who came through organic search, direct, and referral. It is the honest top-line number for a CFO because it captures the true cash cost of growth, regardless of which channel gets credit.
Channel-attributed CAC isolates spend and conversions per channel: Meta CAC, Google Ads CAC, TikTok CAC. This is what you need to make in-flight budget decisions. The Blended CAC vs Paid CAC distinction matters because a healthy blended number can hide a paid channel that is bleeding, and a high paid CAC can look catastrophic until you remember organic is doing half the work.
Same store, three ways of reporting CAC
The chart above uses a single illustrative Shopify apparel store with €40k monthly paid spend and 650 new customers, of whom roughly 420 were paid-attributed. Same business, three legitimate numbers. The version you choose determines whether your LTV:CAC ratio looks like 2.1 or 4.0.
Channel-level CAC benchmarks
Once you can compute CAC honestly at the blended level, the next step is breaking it out by channel. CAC by channel exposes where your acquisition economics are actually working and where you are subsidising losers with winners.
The table below shows typical ranges for online stores in the €1M–€15M revenue band, across the channels most retail brands actually use. Treat these as orientation, not targets — vertical and average order value swing them substantially.
Typical CAC ranges by channel for DTC stores (€1M–€15M revenue band)
| Channel | Apparel & accessories | Beauty & personal care | Home & electronics |
|---|---|---|---|
| Meta Ads (prospecting) | €28 – €55 | €22 – €45 | €45 – €90 |
| Google Search (non-brand) | €35 – €70 | €30 – €60 | €55 – €120 |
| Google Shopping | €20 – €45 | €18 – €38 | €38 – €85 |
| TikTok Ads | €18 – €40 | €15 – €35 | €40 – €90 |
| Affiliate / influencer | €25 – €60 | €20 – €50 | €50 – €110 |
| Organic search (allocated) | €5 – €15 | €4 – €12 | €8 – €22 |
| Blended CAC | €30 – €55 | €25 – €45 | €55 – €95 |
Organic search has a non-zero allocated CAC because SEO content, technical work, and the team time behind it are real costs even when no media is bought. Stores that report €0 organic CAC are flattering themselves; finance will notice eventually.
Common pitfalls and how to avoid them
The first pitfall is the new-customer denominator. If you count every order rather than every new customer, CAC collapses and you have effectively reinvented order acquisition cost. Tie CAC to first orders only — your Shopify or WooCommerce data has the customer_created_at field you need.
The second is timing mismatch. Spend in October often acquires customers whose first order lands in November. For monthly reporting this averages out; for sharp budget changes or seasonality spikes it can distort CAC by 20–40% in a single month. A trailing 30- or 60-day window smooths it without hiding trends.
Run the numbers cleanly with the CAC Calculator
The CAC Calculator handles the blended-versus-paid split, lets you toggle whether to include salaries and discounts, and outputs LTV:CAC and payback period alongside the headline number. Useful for sense-checking the version finance is about to publish.
Frequently asked questions
CAC equals total acquisition spend in a period divided by the number of new customers acquired in that same period. For a store that spent €40,000 in October and acquired 800 new customers, CAC is €50.
For internal reporting yes — fully-loaded CAC including marketing salaries, tools, and creative production is the honest number. For channel-level decisions, a leaner paid-media CAC is more actionable because it changes when you change spend.
In blended CAC, yes — organic, direct, and referral customers go in the denominator because total spend is in the numerator. In paid CAC you exclude them and only count customers attributed to paid channels. Reporting both side by side is the cleanest approach.
Blended CAC divides all acquisition spend by all new customers. Paid CAC divides paid media spend by paid-attributed customers only. Blended is the truer cash cost of growth; paid is the lever you actually pull in a media meeting. See Blended CAC vs Paid CAC for a deeper comparison.
Take spend attributed to that channel (Meta, Google, TikTok, etc.) and divide by new customers attributed to it in your analytics. Choose one attribution model — last non-direct click is the common default — and stick with it across channels so the comparison is fair.
Yes. A 15% welcome discount is an acquisition cost in everything but name. Either add the discount value to acquisition spend, or net it out of first-order revenue before computing contribution margin. Otherwise CAC understates the real cost.
Monthly is standard for reporting. For decision-making, a rolling 30- or 60-day window absorbs the lag between spend and first order. Quarterly windows are useful for board-level views but too coarse for in-flight budget changes.
For online retail, 3:1 is the textbook target — every euro of acquisition cost returns three euros of customer lifetime value. Below 2:1 signals unprofitable growth; above 5:1 often means you are under-investing in acquisition.
Payback period is how many months of contribution margin per customer it takes to recover CAC. With a €50 CAC and €20 monthly contribution margin per customer, payback is 2.5 months. Most DTC stores aim for under 6 months on paid channels.
Almost always a definition mismatch. Agencies typically report paid CAC against platform-attributed conversions; your blended CAC pulls from Shopify or your warehouse and uses last-click or data-driven attribution. Align on what is in the numerator and the denominator before debating the number.
Track CAC, channels, and funnel conversion in one place
Metricuno connects ad spend, funnel events, and revenue so you can see CAC by channel, cohort, and campaign — without stitching together five tools.