Customer acquisition cost. What did the new customer cost?

What is customer acquisition cost?

Customer acquisition cost, or CAC, is the acquisition spend you include divided by the number of new paying customers acquired in the corresponding period. Define the scope before quoting the result: a media-only measure and a fully loaded acquisition measure answer different questions.

For a business-level view, include the relevant sales and marketing costs of acquisition. For a channel-specific view, state how costs and customers are assigned to that channel. Do not label a media-only calculation as fully loaded CAC.

Use first-time buyers in the denominator. If your store records 200 orders but only 80 new customers, dividing acquisition spend by all 200 orders understates what each new customer cost.

Separate CAC from cost per order.

The advertising cost $20 per order, but $62.50 per new customer after the included acquisition costs. Both can be useful. They cannot be substituted for each other.

This is simplified planning arithmetic, not a claim that every order or customer was caused by the ads. If the business serves both repeat buyers and first-time buyers, document how acquisition-only costs are separated from retention work.

Choose and label the cost scope.

• Media. The spend associated with acquiring the customers in your calculation.
• People and management. The portion of internal or agency costs attributable to acquisition.
• Supporting tools and activity. Include relevant acquisition software and other costs, with a consistent allocation rule.

Avoid counting the same economic cost twice. For example, if your first-order contribution already uses revenue after an acquisition discount, do not subtract the discount again when comparing contribution with CAC. Record the convention so the comparison can be reproduced.

A fully loaded view helps assess the investment. A media-only view can help an operator assess campaign decisions. Keep both if useful, with clear labels and consistent inputs from one review to the next.

What is a good CAC for ecommerce?

A good CAC fits the contribution the customer is expected to produce and the time your business can afford to wait for it. There is no useful universal dollar target across stores with different products, margins and repeat-purchase patterns.

For a first-order view, calculate what the new customer’s order leaves before acquisition costs. If a $100 net order costs $65 to fulfil, $35 is available. A fully loaded CAC of $25 leaves $10 before any other omitted costs. A CAC of $40 creates a $5 first-order shortfall.

If management and other acquisition costs are already included in CAC, do not deduct them from that same contribution a second time. You can instead compare a media-only allowance with media-only acquisition cost; make the choice explicit.

Our advertising economics calculator works on an entered group of orders. It shows cost per order and the contribution available for ad spend. Use a new-customer-only order group if you want to examine first-order economics, and keep it distinct from a fully loaded CAC calculation.

Use customer value you can substantiate.

A business with reliable repeat purchases may accept a first-order shortfall. The case depends on later contribution, the likelihood of those purchases and cash payback—not just a projected lifetime revenue number.

Group customers by when they first bought. Look at settled revenue, fulfilment costs, returns and retention spend over a defined window. Keep recent cohorts separate from mature ones: a new customer has not yet had the same opportunity to return.

If a cohort contributes $20 per customer initially and another $15 over the following three months, that is $35 of observed contribution across that window before any excluded costs. A $30 CAC would recover within the window only if the included timing and costs support it. It does not mean future cohorts will behave the same way.

Improve the buying response before chasing cheaper attention.

A lower click price can help. It is not enough if fewer of those people become worthwhile new customers. Examine which buying arguments earn purchases, what offer people choose and the contribution of the customers the campaigns acquire.

Review CAC alongside ROAS and margin, customer mix and payback. When spend increases, ask whether the additional customers still justify their cost. Agree which costs and reporting windows are in scope before making that decision.

This is where Run Ads earns its role. We manage Meta and Facebook advertising around a clear reason to buy and a commercial standard for the response. Send your store, current acquisition costs and the growth you need. We will discuss the work and the fee before you commit.