Marketing and acquisition
Customer acquisition cost (CAC) calculator
Customer acquisition cost is what you spend to win one new customer. Add up everything sales and marketing consumed over a period, then divide by the customers that spending actually brought in.
Media, salaries, agency fees, tools, content
Only the customers this spending won
The formula
- Sales and marketing
- Everything spent to acquire customers over the period. Media, agency fees, creative production, the salaries of the people doing the work, the tools they use, and whatever content cost to make. Most reported CAC figures include the media and stop there, which is the single largest reason the number comes out wrong. Salaries and tools are frequently the majority of the total for a small team.
- New customers
- Only the customers this spending won, and only ones who actually bought. Not leads, not signups, not everyone who appeared in the period. If a third of your new customers arrived through referral and organic search while the budget was running, including them in the denominator credits paid acquisition with work it did not do.
A worked example
The same outdoor gear brand from the ROAS example spends 10,000 on media in a quarter and reports 160 new customers. The number that circulates internally is 62.50 per customer, and against a 250 average order it sounds comfortable.
Then add what the media alone left out. The agency retainer was 3,000, the marketing coordinator costs 5,000 of allocated salary for the quarter, and the email and analytics stack is 2,000. Sales and marketing actually consumed 20,000, so CAC is 125. The figure doubled without a single thing about the campaign changing.
Now fix the denominator. Of those 160 new customers, 40 came through referral and organic search and would have arrived whether or not the campaign ran. Paid acquisition won 120, so the honest CAC is 167. The number that started at 62.50 is closer to 167, and every decision made on the first figure was made on a number roughly a third of the real one.
What 167 means depends on what a customer is worth. At a 250 average order and a 30 percent gross margin, the first purchase contributes 75. Acquisition loses 92 on every new customer up front, which is a perfectly sound position if they come back and a fatal one if they do not. That question belongs to lifetime value, and CAC cannot answer it alone.
When to use it
CAC is the right measure when the question is what growth costs. It sits underneath almost every budget argument worth having: whether to raise spend, whether a channel earns its place, whether the sales team pays for itself. Unlike ROAS, it is built to hold salaries, tools, and fees, which is why it is the number to reach for once the conversation moves past media efficiency.
It is most useful tracked over time rather than read once. A CAC that climbs quarter over quarter while spending stays flat is the clearest early signal that a channel is saturating, and it shows up in this number well before it shows up in revenue.
Report it two ways and label both. Blended CAC divides all sales and marketing by all new customers and answers what growth costs the business overall. Paid CAC divides paid spending by paid-acquired customers and answers whether the advertising works. Both are legitimate, they are not interchangeable, and confusing them is how a healthy blended figure conceals an unprofitable paid channel.
Where it misleads
The denominator is where most of the damage happens. Counting every new customer against paid spending flatters the result, sometimes dramatically, because organic and referral customers cost the campaign nothing to win. The more successful your organic presence, the more this error understates what paid acquisition actually costs.
The numerator has the opposite problem in one specific case. Brand and content spending pays out over years, not quarters, so charging all of it against this period overstates CAC while the investment is being made and understates it later. There is no clean answer to this. Pick a treatment, write it down, and stay with it, because the trend over time is worth more than any single quarter figure.
Timing rarely lines up either. Spending happens in one period and customers close in the next, and the longer the sales cycle the worse the mismatch. For anything with a cycle beyond a few weeks, compare spending against the customers that spending plausibly produced rather than against whoever happened to close inside the same calendar boundary.
CAC in isolation says nothing about whether the business works. A high figure is fine if customers stay for years and a low one is dangerous if they buy once. The number only becomes a judgement when read against the LTV to CAC ratio and against how long the money takes to come back, which is payback period.
An average across channels hides the ones losing money. A blended 167 can be made of one channel at 80 and another at 400, and the blend keeps the second one alive. Break it apart by channel before deciding anything about the budget.
Frequently asked
What is a good customer acquisition cost?
There is no universal figure, because it depends entirely on what a customer is worth and how long they stay. The usual test is the ratio of lifetime value to acquisition cost, where roughly 3:1 is widely cited as healthy. A CAC that looks high against a high lifetime value is a better position than a low one against a single purchase.
What costs should be included in CAC?
Everything sales and marketing consumed to win customers: media, agency fees, creative, content production, the tools the team uses, and the salaries of the people doing the work. Excluding salaries is the most common omission and it frequently understates the figure by half or more for a small team.
What is the difference between CAC and CPA?
Cost per acquisition usually measures the cost of a conversion event such as a lead or a signup, and is typically calculated on media spending alone. Customer acquisition cost measures the cost of winning a paying customer and is meant to include the full cost of the function. CAC is the larger number and the more honest one.
What is the difference between blended CAC and paid CAC?
Blended divides all sales and marketing spending by all new customers, including those who arrived organically. Paid divides paid spending by only the customers paid acquisition won. Blended answers what growth costs the business, paid answers whether the advertising is working, and reporting one while calling it the other hides an unprofitable channel.
Should salaries be included in customer acquisition cost?
Yes. The people running acquisition are a cost of acquiring customers, and for a small team they often outweigh the media budget. Allocate the share of each salary that goes to acquisition work rather than the whole figure where someone splits their time.
Numbers are the easy part
Getting the calculation right takes two inputs. Getting an organization to agree on what counts as gain, what counts as cost, and what the number should change takes considerably longer.
That translation work is most of what I do. Westphal Solutions builds websites, tools, and reporting for nonprofits and growing teams, including the kind of measurement setup that makes a number like this one worth trusting in the first place.
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