CAC in B2B: how to calculate customer acquisition cost right

CAC, customer acquisition cost, is calculated by dividing all sales and marketing costs over a period by the number of new customers won in that same period. Sounds simple, but most B2B companies calculate it too low because they forget half the costs. Here is the full calculation and the most common misses.

What is the formula for CAC?

The base formula is straightforward:

CAC = total sales and marketing costs / number of new customers

Spend 300,000 on sales and marketing over a quarter and win 10 new customers, and your CAC is 30,000. The number only becomes useful if the numerator actually contains everything. It rarely does.

Which costs get forgotten most often?

Most people count ad budget and maybe sales salaries. Then it stops. An honest CAC calculation also includes:

• Salaries including payroll taxes for everyone who works on sales and marketing, part time included. The founder's selling hours count too.
• Tools and licenses. CRM, email tools, data sources, analytics platforms.
• Content and agency costs. Freelancers, designers, consultants.
• Commissions and bonuses.
• Ramp and recruiting. The cost of hiring and training salespeople lands in practice on customer acquisition.
• Events and travel. Trade shows, customer dinners, sponsorships.

Miss these items and your real CAC can be twice the one you report.

What is fully loaded CAC and why does it matter?

Fully loaded CAC is the number with all the items above included, not just direct campaign costs. The difference is rarely small:

It is the fully loaded number that decides whether your business model holds. Pricing, margins and growth rate all rest on knowing what a customer actually costs, not what the ad account shows.

How often should you measure CAC?

Quarterly is enough for most companies between 11 and 100 employees. Monthly gets noisy when you win few customers per month. Measure per channel too, because the average often hides the fact that one channel carries the whole load while another burns money.

Also account for the lag. Costs you take in January often produce customers in April. With long sales cycles, compare the costs to the customers one sales cycle later.

Why does reactivating old leads lower your CAC?

Here is the biggest lever that few people calculate. Every lead in your CRM is already paid for. You spent ad money, event costs or sales time to get the contact, and a new lead costs on average a few thousand to generate. Yet industry data shows that 70 to 80 percent of all leads in a CRM never get followed up.

When you wake a dormant lead and it becomes a customer, the acquisition cost is essentially just the cost of the follow up itself. No new ad spend, no new list, no new data enrichment. That drops your average CAC immediately, and it is often the fastest path to more customers without a bigger budget. That is exactly the logic Revexa builds Leo around: existing leads are the cheapest pipeline you have.

If you want to see what sits in your own database, you can run the numbers in the calculator.

Common questions

What is a good CAC in B2B?

It depends entirely on customer value. The rule of thumb is that lifetime value (LTV) should be at least 3 times CAC. A CAC of 60,000 is excellent if the customer is worth 300,000 over their lifetime.

Should you include salaries in CAC?

Yes. A CAC without salaries is a marketing number, not a business number. Calculate it fully loaded with payroll taxes.

How does CAC differ between new and reactivated customers?

A reactivated customer only carries the cost of the follow up, because the lead itself is already paid for. In practice, CAC for reactivated customers can be a fraction of CAC for entirely new ones.