Customer Acquisition Cost Calculator

Two numbers decide whether marketing is an investment or a leak: what a customer costs to win, and what that customer is worth over the whole relationship. This calculator works out both, along with how long it takes to earn the money back and the most you can sensibly pay for a new customer.

Customer Acquisition Cost Calculator

What a customer costs to win, and what they are worth.

$
Ads, agency fees, tools, commissions, and sales salaries.
Only genuinely new customers, not repeat orders.
$
What a typical order or job is worth.
How often a typical customer buys. Use 1 for one-off work.
years
How long a customer keeps buying before they stop.
%
What is left of a sale after its direct costs.

Cost to acquire one customer

—

—Lifetime value (gross profit)
—LTV to CAC ratio
—Payback period
—Gross profit per customer per year
—Most you should pay
—Profit per customer after CAC
—Lifetime revenue per customer

What a change in spend would mean

Monthly spendCustomers at this CACLifetime gross profit addedReturn

Estimates only. Results update as you type. Nothing you enter leaves your browser.

Customer acquisition cost

CAC is everything you spent to win customers, divided by the number you actually won. Include the obvious costs and the ones people leave out: ad spend, agency or freelancer fees, marketing software, sales commissions, and the portion of salaries that goes to selling. Leaving those out produces a flattering number that leads to bad decisions.

CAC = Total sales and marketing spend ÷ New customers won

Lifetime value

LTV is the gross profit a customer generates over the whole relationship, not the revenue. Revenue-based LTV is the most common mistake in this calculation, and it can make a losing channel look like a winner. A customer who spends $1,000 a year on a product with a 20% margin is worth $200 a year to you, not $1,000.

LTV = Average sale × Purchases per year × Years as a customer × Gross margin

The ratio that matters

Divide LTV by CAC. A ratio of 3 to 1 is the widely used benchmark: it leaves enough after acquisition to cover overhead and still make a profit. Below 1 to 1 you lose money on every customer. Between 1 and 3 you are profitable at the unit level but may not be after overhead.

Much above 5 to 1 is not automatically good news. It often means you are under-investing and leaving growth on the table, because you could afford to bid more, hire a salesperson, or enter a channel you have been avoiding.

Payback period

The ratio tells you whether the economics work. The payback period tells you whether your cash can survive them. If a customer takes eighteen months to repay their acquisition cost, every new customer is a cash outflow for a year and a half, and fast growth will drain the bank account even though the business is profitable on paper. Under twelve months is comfortable for most small businesses; under six is strong.

Five ways to improve the ratio

  • Raise prices. It lifts LTV immediately with no extra acquisition cost, and it is the lever owners reach for last.
  • Increase purchase frequency. A customer who buys four times a year instead of three is worth a third more, and they already know you.
  • Keep customers longer. Lifespan multiplies straight through LTV. The churn rate calculator shows what retention is worth in your business.
  • Ask for referrals. A referred customer often costs almost nothing to acquire and stays longer, which improves both halves of the ratio at once.
  • Measure by channel. A blended CAC hides everything. One channel is usually carrying the average while another quietly wastes money.
How AI can help: Put your ad platform exports and your sales records in front of an AI assistant and ask it to work out cost per acquired customer by channel and by month, then flag which channel's cost is rising fastest. The arithmetic is simple but the data is usually scattered across four places, which is why most owners never do it. Ask for the calculation it used so you can check it, since matching spend to customers involves assumptions worth seeing.

Frequently asked questions

What is a good LTV to CAC ratio?

3 to 1 is the standard benchmark: three dollars of lifetime gross profit for every dollar spent acquiring the customer. Below 1 to 1 you lose money per customer. Above about 5 to 1 you are probably under-spending and could grow faster.

Should LTV use revenue or profit?

Gross profit. Using revenue inflates lifetime value by the size of your cost of goods and is the most common reason a channel looks profitable when it is not. Multiply by your gross margin.

What costs go into CAC?

Everything spent to win new customers: advertising, agency and freelancer fees, marketing software, sales commissions, trade shows, and the share of salaries spent selling. Exclude the cost of serving customers you already have.

How do I estimate customer lifespan if I am new?

If you have no history, start with an educated guess based on your industry and revisit it in six months. A simpler alternative is one divided by your monthly churn rate, which gives the average lifespan in months once you have enough data to measure churn.

How often should I check CAC?

Monthly, as part of your regular review, and by channel rather than blended. Acquisition costs drift upward gradually, and a blended figure hides the channel that is drifting fastest.

More free small business calculators

Churn Rate CalculatorHow fast you lose customers, and where revenue lands in a year.ROI CalculatorPayback period and return on equipment, software, or a campaign.Profit Margin & Markup CalculatorSet prices from a target margin, or check what a price really earns.Monthly Business ReviewTen minutes, seven numbers, and a grade for the month you just closed.

See all thirteen on the small business calculators page.

These calculators give planning estimates, not tax, legal, or financial advice. Check important decisions with your accountant or lender.

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