How to Calculate Customer Acquisition Cost (CAC)

To calculate customer acquisition cost (CAC), add up all your sales and marketing costs for a period and divide them by the number of new customers you won in that same period. The formula is simple. The hard part is everything around it: which costs to include, who counts as a customer and how to compare an online ad with a poster or a campaign in restaurants. Below you'll find the formula and its variants, what to include, CAC vs CPA vs CPL, a worked offline example, LTV and a channel comparison table.

The customer acquisition cost formula

The basic formula looks like this:

CAC = customer acquisition costs in a period ÷ number of new customers acquired in that period

You'll come across two ways of slicing it. The first is which customers you count:

• Blended CAC: all sales and marketing costs divided by all new customers, including those who came through referrals or found you on their own. It shows the health of the business as a whole but hides the differences between channels.
• Channel or campaign CAC (called paid CAC when it covers paid channels only): the costs of one channel divided by the customers you can attribute to it. This is the number you use to decide where to move budget.

The second is which costs you include. A simple CAC uses media spend only. A fully loaded CAC adds production, agency fees, tools and your team's time. Both are useful, as long as every report says which one you're looking at.

Before you calculate anything, settle two things.

Who counts as a customer. For a pilates studio, someone who buys a first class pass; for a property developer, someone who signs a reservation agreement; for an app, a user who pays for a subscription. A redeemed promo code or a free class booking isn't a purchase yet. Track the cost of those actions too, but under a different name (more on that below).

Which period you're measuring. You pay today, and the customer buys in two weeks or next quarter. Pick a fixed window, such as “campaign duration plus 30 days”, and use it for every channel.

What to include in CAC (and what to leave out)

A common mistake is counting only the advertising budget. That kind of CAC looks good in a report, but it doesn't tell you what a customer really costs. A fully loaded CAC covers everything you wouldn't have spent if you weren't trying to win new customers.

CAC vs CPA vs CPL: what's the difference?

These three abbreviations often get lumped together, but they measure different stages of the customer journey.

The link between the three is simple. Illustrative example (made-up figures to show the relationship): a campaign cost PLN 4,000, generated 80 leads, and one in four leads made a purchase.

• CPL = PLN 4,000 ÷ 80 = PLN 50,
• there are 20 customers, so CAC = PLN 4,000 ÷ 20 = PLN 200, which is the CPL divided by 25%.

The practical takeaway: a cheap lead doesn't mean a cheap customer. A channel with a low CPL and weak lead-to-sale conversion can end up with a higher CAC than one that brings fewer but better contacts. Also be careful with “CPA” or “cost per conversion” in ad platform dashboards: it usually counts media spend only, and some teams use CPA to mean cost per customer, so write down your definition.

How to calculate CAC for an offline campaign (illustrative example)

You can't attribute customers to an offline campaign automatically, the way you can with ad clicks. You need an identifier that travels from the ad all the way to the sale.

1. Give the campaign its own marker: a promo code, a QR code with a campaign parameter or a short web address used only on that medium. If you run the campaign in several locations or districts, give each one a separate marker.
2. Define a customer (for example: bought a class pass within 30 days of redeeming the code).
3. Collect all the costs using the table in the previous section.
4. Count the customers within the agreed window and divide.
5. Check how many customers would have come anyway. Some code users are regulars or people who were already planning to buy. How to estimate that with a control group is covered in our guide to offline marketing attribution.

Illustrative example (all figures are made up and are not a price list for any medium): a pilates studio runs a one-month campaign in the city with a “free first class” offer.

48 people redeemed the code, and 30 of them bought a class pass within a month. Depending on the definition, you get three different numbers:

• cost per redemption, budget only: PLN 6,000 ÷ 48 = PLN 125,
• full cost per redemption: PLN 9,080 ÷ 48 ≈ PLN 189,
• fully loaded CAC per paying customer: PLN 9,080 ÷ 30 ≈ PLN 303.

Each of them is correct, as long as you know what you're counting. The first is good for comparing the efficiency of the medium itself; the last tells you whether the campaign pays off. That's also how the “Cost per customer” card works in the Fortuners panel demo: on demo data, it divides the campaign budget by the number of people who used the code. Production on the brand's side, team time and actual pass sales go into your own spreadsheet.

CAC and LTV: when a customer pays off

CAC on its own won't tell you whether PLN 303 is a lot. You need the other side of the equation: LTV (lifetime value, also called customer lifetime value or CLV), meaning how much margin an average customer leaves with you over the whole relationship.

A simple formula is enough for a small or medium-sized business:

LTV = average monthly spend × average number of months as a customer × gross margin (%)

Illustrative example (still made-up figures): a studio client pays PLN 280 a month for a class pass, stays for five months on average, and the gross margin on the pass is 60%.

• LTV = PLN 280 × 5 × 0.6 = PLN 840
• LTV to CAC ratio = PLN 840 ÷ PLN 303 ≈ 2.8
• CAC payback period = PLN 303 ÷ (PLN 280 × 0.6) ≈ 1.8 months

What is a good LTV to CAC ratio?

The most widely quoted rules of thumb come from SaaS. In SaaS Metrics 2.0 (opens in a new tab), David Skok writes that the best SaaS businesses have an LTV to CAC ratio higher than 3, and that profitability suffers when it takes more than 12 months to recover CAC. He also stresses that these are guidelines, not hard rules.

Treat them as a reference point, not a standard for a studio, a salon or a developer. Two questions matter more: does the acquisition cost come back before you run out of cash for the next campaign, and is the result improving over time? In the example above the ratio is just under 3, but the studio earns back each customer's cost in under two months.

Channel comparison: a template to fill in

Copy this table into a spreadsheet and update it after every campaign. The rows are examples, so add your own channels.

To keep the comparison fair:

• One customer definition for every row.
• One time window (for example, the campaign plus 30 days).
• Full costs in every row, including “free” channels such as referrals (rewards, time spent running the scheme).
• The attribution column is mandatory. For channels without a code, ask “How did you hear about us?” at the point of sale and record the answers.

Decide how you'll calculate CAC before launch, not after the results come in. The one-page scenario template in our article on marketing campaign examples for local brands has a field for exactly that.

5 ways to lower customer acquisition cost

1. Choose the place, not the reach. A low cost per contact won't give you a low CAC if most of the people you reach will never become customers. For a local business, what counts is reaching people nearby, in a situation connected to the offer. We cover choosing those places in our local marketing strategy guide.

2. Fix the path after the scan or click. A mobile-friendly offer page, one offer instead of the full price list, a two-field form. Every extra step means fewer customers for the same spend.

3. Test offers against paying-customer CAC. A freebie may bring more redemptions than a discount, but also more people who never come back. Compare offer variants by the cost of a paying customer, not of a redemption.

4. Respond to leads the same day. A class booking or an enquiry about a flat goes cold quickly. Decide who replies and how fast, and check it in your CRM.

5. Switch off channels after a fair test. Give each channel the same time and enough budget to collect data. A channel that still has the highest CAC after two or three rounds, with no sign of improvement, hands its budget to the ones that work.

If you're considering a channel where the cost per redemption is visible from day one, see how a fortune cookie campaign works: every campaign has its own QR code and promo code, and you track scans, redeemed codes and cost per redemption in the panel.

Frequently asked questions

• How do you calculate customer acquisition cost?+

  Add up all sales and marketing costs for a period (media, production, agency fees, tools, team time and discounts for new customers) and divide the total by the number of new customers acquired in the same period. For the CAC of a single channel, use only the costs and the customers attributed to that channel.

• What is the difference between CAC, CPA and CPL?+

  CPL is the cost of acquiring a contact (a lead), CPA is the cost of a defined action, such as an app install or a code redemption, and CAC is the cost of acquiring a new paying customer, usually calculated with full costs rather than media spend alone. Some teams use CPA to mean the cost per acquired customer, so always write down your definition.

• What is a good LTV to CAC ratio?+

  The most widely quoted rule comes from SaaS: the best SaaS businesses have an LTV more than three times their CAC. It is a reference point, not a standard for every industry. A local service business should first check whether the margin from a customer pays back the cost of acquiring them within a time frame it can afford.

• Should discounts for new customers be included in CAC?+

  Yes, if the discount or freebie exists only to win the customer. Include its real cost (for example, the cost of running a free class) rather than the list price, and don't subtract it again from revenue when you calculate LTV.

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