How Much Does It Cost to Win a Client: CAC for Agencies

Agencies love to track how much they earn on a client, but they almost never track what it cost to win that client. And that's half the economics: a client can bring a healthy margin and still be unprofitable if winning them cost more than they'll ever pay back. The number that shows this is CAC — customer acquisition cost.

Let's break down what CAC is, how to calculate it, and what to do with it.

What CAC is and why an agency should track it

CAC (customer acquisition cost) is the average amount an agency spends to land one new client. It answers the question: how much does each client's «yes» cost. Without this number you don't know whether your sales and marketing pay off, and you easily fall into a trap — acquiring clients at a loss while celebrating growth.

What goes into the cost of acquiring a client

CAC includes everything spent on finding and closing clients over a period: ad budget, salaries of salespeople and marketers, lead-generation contractors, time spent preparing proposals and presentations. That last one is often underestimated — the team's hours on free pre-sales are also an acquisition cost, even if they never run through an ad account.

How to calculate CAC

The formula is simple: CAC = all acquisition costs for a period / number of new clients over the same period. If over a quarter you spent 150 thousand on sales and marketing and landed 10 new clients, CAC = 15 thousand. That's the average «cost of entry» for one client, and it's exactly what you should compare against what the client brings you.

CAC on its own means nothing

Is 15 thousand a lot or a little? The answer depends solely on how much a client brings over the entire relationship. If an average client delivers 200 thousand in profit over two years, a CAC of 15 thousand is great. But if the client leaves after a month, having left behind 20 thousand, that same CAC is already dangerous. That's why CAC is always read alongside client value, and seeing who brings how much is exactly what P&L by client helps with.

Example: an agency's CAC

In one month an agency spent 120 thousand on acquisition: ads 40, sales team salaries 60, team hours on pre-sales ~20. Eight new clients came in. CAC = 120 / 8 = 15 thousand per client. The average client brings 12 thousand in profit per month and stays for an average of 10 months — that's 120 thousand over the whole relationship. So acquisition pays off by the second month, and after that the client works in the black. The model is healthy. But if clients left after 1–2 months, a CAC of 15 thousand would eat up all the profit.

How to lower CAC

The cheapest clients are the ones who come in without ads: referrals, repeat business, word of mouth. So the strongest lever for lowering CAC is happy existing clients and reputation. Next comes working on conversion (less pre-sales wasted on the wrong leads), focusing on the channels that actually bring clients, and dropping the ones that only burn budget. Comparing the profitability of channels and directions is what the article Margin by direction helps with.

In Finmap, sales and marketing spend is visible separately, so you can calculate CAC and compare it against what clients bring on real data. Try it free for 7 days.