CAC (customer acquisition cost) is how much it costs your business to win one new customer. The formula is CAC = total sales and marketing costs ÷ new customers. If you spend $12,000 in a month on marketing and sales and win 120 new customers, your CAC is $100. The CAC calculator above works that out for you. Add a customer lifetime value and it also shows your LTV:CAC ratio.
In short
- CAC = total sales and marketing costs ÷ new customers won in the same period.
- Count everything it costs to win customers: ad spend, but also salaries, commissions, tools and agency fees.
- CAC on its own doesn’t tell you much. Compare it with what a customer is worth over time (customer lifetime value, or LTV).
- A common rule of thumb is an LTV:CAC ratio of 3:1 or higher. It’s a guide, not a law.
- Payback period shows how many months it takes to earn back what you spent on a customer.
What is customer acquisition cost?
Customer acquisition cost, or CAC, is the average amount you spend to turn a stranger into a paying customer. It covers the whole path: the ads that got attention, the people and tools that followed up, and the offer that closed the sale.
It’s one of the most watched numbers in online business because it shows whether growth is affordable. If you can win a customer for $50 and they’re worth $500, you can grow quickly. If you pay $500 to win a customer worth $200, every new sale makes the problem bigger.
CAC is part of your unit economics, the numbers that show whether one customer makes money for the business. The other key parts are customer lifetime value, margin and payback period.
How to calculate CAC?
Add up everything you spent to win customers in a period, then divide by the number of new customers you won in that same period.
| What you want | Formula |
|---|---|
| CAC | (marketing costs + sales costs) ÷ new customers |
| LTV:CAC ratio | customer lifetime value ÷ CAC |
| New customers from a budget | budget ÷ target CAC |
| Budget needed | target CAC × customers wanted |
| Payback period (months) | CAC ÷ (monthly revenue per customer × margin) |
The calculator does the first formula and the ratio. The others are quick to do by hand.
Here are the steps:
- Choose a period, such as last month or last quarter.
- Add up your marketing costs: ad spend, creative, marketing tools and the pay of the people who run marketing.
- Add up your sales costs: sales salaries, commissions and sales tools.
- Count the new customers you won in the same period.
- Divide total costs by new customers.
In a spreadsheet, put total costs in A2 and new customers in B2, then type =A2/B2.
Count new customers only. Repeat purchases from existing customers don’t belong in the number, because they didn’t cost you an acquisition.
CAC examples
Example 1: find the CAC
You spent $8,000 on marketing and $4,000 on sales, for $12,000 in total. You won 120 new customers. CAC = 12,000 ÷ 120 = $100.
Example 2: ad spend only versus the full cost
Using only the $8,000 of marketing gives 8,000 ÷ 120 = $66.67. That number looks better, but it leaves out $4,000 of real cost. The $100 figure is the one that tells you what winning a customer really costs.
Example 3: find the customers (by hand)
You have a $5,000 budget and a target CAC of $125. New customers = 5,000 ÷ 125 = 40.
Example 4: find the budget (by hand)
You want 200 new customers at a $90 CAC. Budget = 90 × 200 = $18,000.
Example 5: check the LTV:CAC ratio
Your CAC is $100 and a customer is worth $350 over their lifetime. LTV:CAC = 350 ÷ 100 = 3.5:1. That’s above the common 3:1 rule of thumb.
Example 6: the same CAC, different outcomes
Two businesses both pay $100 to win a customer. Business A’s customers are worth $120 over their lifetime, a ratio of 1.2:1. Business B’s customers are worth $500, a ratio of 5:1. The CAC is identical, but A is barely breaking even and B has plenty of room to grow.
Example 7: find the payback period (by hand)
Your CAC is $120. A customer pays $50 a month, and you keep 60% of that after product costs, which is $30 of profit a month. Payback = 120 ÷ 30 = 4 months.
Fully loaded CAC vs paid CAC vs blended CAC
You’ll see a few versions of CAC.
| What it includes | Best for | |
|---|---|---|
| Paid CAC | ad spend only, divided by customers won through paid channels | judging ad campaigns |
| Blended CAC | all costs, divided by all new customers, paid and organic | judging overall efficiency |
| Fully loaded CAC | all sales and marketing costs, including salaries, tools and agency fees | judging whether the business can afford to grow |
Paid CAC is useful for comparing campaigns. But it flatters you, because it leaves out the people, tools and agencies that make the ads work. When you’re deciding whether the business is healthy, use fully loaded CAC.
To see paid CAC in the calculator, enter only your ad spend as marketing costs. For fully loaded CAC, add everything.
What is customer lifetime value (LTV)?
Customer lifetime value, also called CLV or LTV, is the total profit you expect to earn from a customer over the time they stay with you.
A simple way to estimate it: average monthly revenue per customer × margin × the number of months they stay. If a customer pays $50 a month, you keep 60%, and they stay 20 months, LTV = 50 × 0.60 × 20 = $600.
For subscriptions, you can estimate the number of months as 1 ÷ your monthly churn rate, which is the share of customers who leave each month. A 5% monthly churn rate means about 20 months. For a shop with repeat buyers, use the average number of orders per customer instead of months.
LTV is an estimate. Use your own data, and be careful with new businesses, because a guess about how long customers will stay can be far off.
What is a good CAC?
There’s no single good CAC. It depends on your industry, price, margin and how long customers stay. A $200 CAC is excellent for a product that earns $2,000 over a customer’s lifetime, and a disaster for one that earns $150.
That’s why an average CAC by industry is a weak guide. Better questions are:
- Is my LTV:CAC ratio healthy? A common rule of thumb is 3:1 or higher. Much lower means customers don’t earn back their cost. Much higher can mean you’re not investing enough in growth.
- How long is my payback period? The shorter it is, the faster cash comes back to fund more growth. Many subscription businesses aim for under a year, but the right answer depends on how much cash you have.
- Does my CAC hold as I spend more? CAC often rises as you scale, because the easiest customers are won first.
CAC vs CPA vs CPL
| What it measures | What’s included | |
|---|---|---|
| CAC | cost to win one new customer | all sales and marketing costs |
| CPA | cost per conversion | usually just ad spend |
| CPL | cost per lead | ad spend divided by leads |
CPA and CPL describe a campaign. CAC describes the business. A campaign can have a great CPA while the business has a poor CAC, because the CPA left out salaries and tools. A conversion isn’t always a customer, either. It might be a signup or a lead that never buys. You can try the CPA calculator for the campaign view.
CAC and the rest of your ad numbers
CAC sits at the end of the chain that starts with impressions:
- You pay for impressions, at a price called CPM.
- Some people click. That’s your CTR.
- Some clicks become customers. That’s your conversion rate.
- What those customers earn you shows up in your ROAS.
Improve any step and CAC falls. A better click-through rate means cheaper clicks, and a better conversion rate means fewer clicks per customer.
How to track CAC
Calculate CAC on a regular schedule, such as every month or every quarter, so you can see the trend. A single number tells you little, but a rising CAC tells you something is getting more expensive.
Break it down where you can:
- By channel. Compare CAC from paid search, social ads, email, referrals and organic search, so you can move budget to what works.
- By customer type. Small and large customers, or new and returning markets, often have very different CAC and LTV.
- By time. Customers won this month may come from spending in earlier months, especially with a longer sales cycle. Compare costs and customers over a long enough window.
How to lower your CAC
- Improve your conversion rate. A clearer page and offer turn more visitors into customers.
- Focus on the channels that work. Look at CAC by channel and shift budget from the worst to the best.
- Use referrals and word of mouth. Customers who come through friends often cost far less.
- Invest in content and SEO. They take time but can bring in customers without paying per click.
- Keep customers longer. It doesn’t lower CAC, but it raises LTV, which has the same effect on your ratio.
- Cut tools and costs that don’t pay for themselves. Fully loaded CAC includes them.
A caution: if you cut CAC by pushing for cheap customers who leave quickly, your LTV can drop even faster. Look at both numbers together.
Common CAC mistakes
- Leaving salaries, tools and agency fees out of the cost.
- Counting returning customers as new ones.
- Using different date ranges for costs and customers.
- Ignoring the time lag between spending and winning a customer.
- Looking at CAC without LTV or payback period.
- Using paid CAC to decide whether the whole business is healthy.
CAC calculator FAQ
How do you calculate CAC?
Divide your total sales and marketing costs by the number of new customers in the same period. For $12,000 and 120 new customers, CAC = 12,000 ÷ 120 = $100.
What is a good CAC?
It depends on what a customer is worth. A good CAC is well below the lifetime value of a customer, and a common rule of thumb is an LTV:CAC ratio of 3:1 or higher.
What is a good LTV:CAC ratio?
Many businesses aim for about 3:1 or higher. A ratio under about 1:1 means you lose money on each customer, and a ratio far above 3:1 can mean you could spend more to grow.
What is CAC payback period?
It’s the number of months it takes a customer to earn back what it cost to acquire them. It equals CAC divided by the monthly profit you make from that customer.
What is the difference between CAC and CPA?
CAC counts all sales and marketing costs per new customer. CPA usually counts only ad spend per conversion, and a conversion may not be a customer.
Should I include salaries in CAC?
For fully loaded CAC, yes. Include the pay of people whose work is to win customers, such as marketers and sales staff, along with tools and agency fees.
Should I include customer service costs in CAC?
Usually not. Customer service counts as retention. Include it only for work that is specifically about winning new customers, such as sales support.
How can I lower my CAC?
Improve your conversion rate, focus on the best channels, get referrals, invest in content and SEO, and cut costs that don’t pay off.
How this calculator works?
The calculator uses standard definitions and runs entirely in your browser, so nothing you type is sent anywhere. I test every result against hand-calculated examples. See How We Calculate for how I test and update the tools. Results are estimates based on the numbers you enter. They aren’t financial advice.
By Ajay Kumar, SEO strategist and content writer. Last updated: October 5, 2026