B2B customer acquisition cost, the well-known CAC, answers a question every business owner should ask before investing in sales: how much do I really spend to bring in a new client? The math starts one step before closing, with the cost of each conversation. To get that number, use the cost per meeting calculator, which compares trade shows, prospecting with an SDR, ads and business rounds, counting your own time. Then follow this guide to get to the CAC of each channel.
What CAC is
CAC is the sum of everything the company spent to win clients over a period, divided by the number of new clients who came in during that same period.
CAC = total marketing and sales cost for the period ÷ new clients in the period
The formula is simple. The hard part is being honest about what goes into the numerator. Many small companies calculate a low CAC because they forget the biggest cost of all: the owner's time.
What goes into the cost
Include everything that exists because of the search for new clients:
- Media and ads: the amount invested in ad platforms, sponsorships and paid posts.
- People: salaries, payroll charges and commissions of those who sell or prospect, in proportion to the time spent on new clients.
- Your time: the hours you spend in meetings, on proposals, at events and prospecting, multiplied by a realistic hourly rate.
- Tools: customer management system, list-building and email tools, subscriptions used by the sales team.
- Events: trade show registration, booth, travel, lodging and meals.
- Materials and agencies: presentation, website, catalog, photos, a marketing agency or freelancer.
What does not go in: the cost of serving and keeping clients who already buy. That is an operating or retention cost, and mixing the two makes the number meaningless.
How to put a value on your time
A practical way is to think about how much you would charge a client for an hour of work, or how much it would cost to hire someone to do what you do. It does not need to be exact. It needs to be more than zero, because every hour spent prospecting is one hour less on operations, on management or with your family.
A CAC calculation example
The numbers below are hypothetical and rounded, chosen only to illustrate the math. They are not a market average or a benchmark for your industry.
Imagine a services company, which we will call Example Company, looking at one quarter:
- Ads: R$ 6,000.
- Tools and materials: R$ 3,000.
- Owner's time prospecting and in meetings: 60 hours at R$ 100 per hour, adding up to R$ 6,000.
Total cost for the quarter: R$ 15,000. During that period, 5 new clients came in.
CAC in the example = R$ 15,000 ÷ 5 = R$ 3,000 per client.
Had the owner forgotten his own time, the math would come to R$ 9,000 ÷ 5 = R$ 1,800. It looks better, but it is a false number, and decisions made with false numbers tend to be costly.
CAC by channel: what changes the decision
The overall CAC shows how much the company spends. The CAC by channel shows where it is worth spending. To calculate it by channel, you need two pieces of information about each one:
- Cost per qualified meeting: how much it costs to get a conversation with someone who fits the profile of a buyer.
- Conversion rate: how many meetings it takes to produce one client.
By multiplying the cost per meeting by the number of meetings needed to close a client, you get that channel's CAC. Here are two hypothetical channels, with illustrative numbers:
| Channel (example) | Cost per meeting | Meetings per client | Channel CAC |
|---|---|---|---|
| Channel A | R$ 250 | 8 | R$ 2,000 |
| Channel B | R$ 600 | 3 | R$ 1,800 |
Notice: channel A has the cheaper meeting, but channel B brings the cheaper client, because its conversations convert better. That is why cost per meeting is the start of the math, not the end. A cheap meeting with someone who does not fit the profile is worth nothing.
Each channel has a role
It also makes no sense to compare channels by the final number alone. Some bring volume, others bring larger clients, others are useful for testing a new market. Trade shows generate in-person contact and visibility. Outbound prospecting lets you choose exactly who to approach. Ads work when people are already searching for your solution. Business rounds bring together companies that have stated what they offer and what they are looking for, which usually shortens the qualification stage. See how a business round works if you want to include this channel in the comparison.
Compare CAC with what the client brings in
Is a CAC of R$ 3,000 high or low? It depends entirely on what the client brings. To answer, look at two measures.
Margin per client over time
Calculate how much gross margin, after the direct costs of delivery, a typical client generates during the whole time they buy from you. This value is known as LTV, or lifetime value. If the LTV does not cover the CAC with room to spare, every new client loses you money, however much revenue grows.
Payback time
Payback time shows how many months it takes for the client's margin to pay back the cost of winning them. Continuing the hypothetical example: if each Example Company client generates R$ 1,000 in margin per month and the CAC is R$ 3,000, payback comes in 3 months. From then on, the client becomes profitable.
For a small company, payback time matters a great deal, because the money spent to win the client leaves your cash before the margin comes in. A channel with a low CAC and slow payback can squeeze your cash more than a channel with a higher CAC and fast payback.
Use CAC to set how much you can spend
CAC also works in reverse: instead of finding out how much you spent, you set how much you can spend. Start with the margin a typical client brings and decide how quickly you want to recover the investment. The result is the maximum acceptable CAC for your company.
One more example with hypothetical, rounded numbers, just to illustrate: if a client brings R$ 800 in margin per month and you want to recover the cost of winning them within 6 months, the maximum CAC is R$ 4,800. Any channel that, after a fair test, brings clients in for less than that deserves more budget. Any channel that brings clients in for much more than that needs to improve its conversion or come out of the plan.
This ceiling helps with day-to-day decisions:
- whether it is worth paying a trade show registration fee, knowing how many meetings it usually yields for you;
- how much commission you can afford to pay a sales representative;
- whether it makes sense to hire someone to prospect or whether it is better to keep doing it yourself;
- how much to invest in a month of ads before assessing the results.
With a ceiling in place, the conversation about the sales budget stops being "how much is left this month" and becomes "how much can each new client cost".
How to estimate CAC without a track record
A new company or a new channel has no track record. Even so, you can estimate before investing heavily:
- Estimate the cost per meeting of each channel with the calculator, using figures close to your reality.
- Assume a conservative conversion rate, worse than you expect.
- Calculate the estimated CAC and compare it with a typical client's margin.
- Choose one or two channels and run a test with a defined budget and timeframe.
- At the end of the test, replace the estimates with the real numbers and redo the math.
A small test costs little and turns guesswork into data from your own company.
Common calculation mistakes
- Forgetting the owner's time: this is the most common mistake and the one that distorts the math the most.
- Mixing periods: in B2B, one month's spending may only turn into a client months later. Use longer periods, such as a quarter, or track by group of opportunities.
- Crediting the channel with a client who came on their own: if the client arrived through a referral, do not credit the close to the ad.
- Looking only at cost per meeting: as the example showed, a cheap meeting does not guarantee a cheap client.
- Calculating once and forgetting: CAC changes over time. Redo the math every quarter.
How to reduce CAC
- Define your ideal customer more sharply: talking to fewer companies, but the right ones, increases conversion.
- Improve your pitch: a clear pitch makes every meeting more productive. The pitch generator helps you get to a short version.
- Ask for referrals: a satisfied client who refers another brings in a new client at a much lower cost.
- Invest in relationships: good business networking generates conversations with people who already know you, and they tend to close with less effort.
- Cut what does not convert: a channel that brings no clients after a fair test should come out of the budget.
Summary
Add up everything you spend to win clients, including your own time, and divide by the new clients in the period. Then calculate the cost per meeting of each channel, multiply it by the meetings needed to close and compare it with the margin the client brings. With that number, choosing a channel stops being a guess.
To test the business round channel with no upfront cost, your company's first online business round is on us: all it takes is an active CNPJ (Brazilian company tax ID), once per CNPJ. See the upcoming business rounds and put the numbers from your conversations into the math.