How to Calculate What Each New Customer Costs You, Using 90 Days of Records

You paid for ads, and now you want to know whether each new customer is worth the spend.

For a small business, customer acquisition cost is the basic number that answers it.

It is a simple division, but it only works when the records are clean and the period is short enough to act on.

Start with a short period of records

Pull every sales and marketing expense for the same period, and count only customers who first bought in that window.

A recent quarter keeps the number close to current reality. A longer window can hide a bad campaign inside a good one.

Include the costs that directly help you find new customers: paid ads, email tools, content, sales commissions, first-purchase discounts, and the software that tracks the result.

Leave out general overhead, repeat customer service, and expenses that would exist even if you stopped marketing.

Done looks like the total spend and the total new customers.

The common mistake is to count repeat buyers as new customers, which makes the cost look lower than it is.

Divide total spend by new customers

Add all sales and marketing investment for the period, then divide by the number of new customers acquired in that same period.

That gives you the cost per new customer, not the cost of keeping an existing customer.

Use the same window for both numbers. If the spend covers a quarter and the customer count covers a different stretch, the result is a guess.

The result is a dollar amount: the amount you paid to get a new customer.

If you have no new customers, the number is not zero. It is a warning that the spend did not produce the result you need.

Keep the worksheet to the essentials: total sales and marketing spend, new customers, and cost per new customer.

If your marketing includes several channels, you can still use a total number first. Break it out by channel only after the total is clear.

Compare your number to the right benchmark

The answer to what is a good customer acquisition cost is not a single number. It depends on what the customer is worth over time and how much margin each sale leaves you.

A tracked set covered 1,600 small business client accounts from November 2025 to May 2026.

The average customer acquisition cost in that set was $250.

A financial advisor or mortgage broker often pays $750 or more for a new client, while a restaurant or pet grooming business often pays under $60.

The spread is wide because a high-value client can justify a higher cost, while a low-price local business needs a much cheaper path to the first sale.

A 2026 CAC benchmark should use recent records, because average small business CAC rose 33% from 2023 to 2026, driven mainly by rising paid advertising costs.

A 2025 data set shows an 18.4% year-over-year CAC increase.

Do not chase the average if your business sells a different kind of value.

Use the range to check whether your number is plausible, then test it against your own margin.

The check is simple: your number, the range, and the margin test.

Decide whether the cost is affordable

Now put the number next to the profit from the first purchase. If the cost is lower than that profit, the customer pays for the marketing before the relationship ends.

A higher cost means you need repeat purchases, a higher price, or a cheaper channel to make the spend work.

A cost close to the first-order profit means you are betting on repeat purchases. That can be fine when the customer keeps buying, but it is risky when cash is tight.

Check the cash flow, not just the margin. A customer can be profitable on paper and still arrive too late to cover the ad spend.

Keep the worksheet short: total spend, new customers, cost per new customer, and the margin left after the first order.

If the number is too high, change the offer, the channel, or the price before you spend more.

The decision is clear: keep the spend, change the channel, or raise the price.