Free Customer Acquisition Cost Calculator

What Is Customer Acquisition Cost?

Customer acquisition cost (CAC) is the average amount you spend on sales and marketing to win one new customer. It is one of the few metrics that decides whether growth makes you money or drains it. If you know your CAC, you know how much you can afford to pay for a customer, which channels are efficient, and whether it is safe to pour more money into ads.

CAC is a management metric, not an accounting figure. There is no GAAP or IFRS rule that defines it, so the only thing that matters is that you measure it the same way every period. The standard definition comes from marketing measurement work such as Farris, Bendle, Pfeifer, and Reibstein in Marketing Metrics, and it is the same version HubSpot and Shopify use in their own CAC explainers.

The Customer Acquisition Cost Formula

The customer acquisition cost formula is simple:

$$\text{CAC} = \frac{\text{total sales and marketing spend}}{\text{new customers acquired}}$$

Two inputs, one number. The care is all in what you count.

• Total sales and marketing spend is every dollar you spent to win customers over the period: ad spend, marketing software and tools, the salaries of the people doing marketing and sales, and any agency, creative, or freelancer costs.
• New customers acquired is the count of net-new, first-time customers over that same period. Do not count repeat orders from existing customers, and make sure the spend window and the customer window line up.

Worked example. Say you spent $5,000 on sales and marketing last month and won 100 new customers:

$$\text{CAC} = \frac{\$5{,}000}{100} = \$50$$

So it costs you $50 to acquire a customer. On its own that number means nothing. $50 is cheap if a customer is worth $400 to you and ruinous if a customer is worth $40. That is why CAC is only half the picture, and why this tool pairs it with lifetime value.

What Is a Good LTV:CAC Ratio?

The single number a store owner should act on is the ratio of customer lifetime value (LTV, also called CLV) to customer acquisition cost. LTV is the total gross profit an average customer leaves with you over their whole life as a buyer. The ratio tells you how many dollars of value you get back for every dollar of acquisition spend.

• LTV:CAC of 3:1 or higher (green) is the classic sign of a healthy, scalable model. Each customer is worth at least three times what you pay to get them, leaving room for overhead and profit.
• 1:1 to 3:1 (amber) is thin. You are profitable on acquisition but leaving money on the table. Raise LTV or cut CAC to reach 3:1.
• Below 1:1 (red) means you spend more to acquire a customer than they are worth. Fix this before you scale ad spend.

The 3:1 rule of thumb is widely attributed to David Skok in SaaS Metrics 2.0. Treat it as a rule of thumb, not a law. A store with high margins and fast payback can run a leaner ratio, while a low-margin store may need more headroom.

Worked example. If your CAC is $50 and your average customer is worth $200 in lifetime gross profit, the ratio is 200 / 50 = 4.0 : 1, comfortably healthy, and net LTV after CAC is $200 - $50 = $150. Enter both numbers in Simple mode and the tool shows the ratio, the verdict badge, and the net value in one view. If you do not know your LTV yet, our customer lifetime value calculator works it out from your average order value, purchase frequency, lifespan, and margin.

What Is the CAC Payback Period?

The LTV:CAC ratio tells you if acquisition pays off eventually. The CAC payback period tells you how fast. It is the number of months of gross profit from a customer it takes to earn back what you spent to acquire them:

$$\text{CAC payback} = \frac{\text{CAC}}{\text{monthly gross profit per customer}}$$

Worked example. With a $50 CAC and $15 of gross profit per customer per month, payback is 50 / 15 = about 3.3 months. Recovering CAC within about 12 months is commonly considered healthy, again a benchmark from growth-metrics writing by David Skok rather than a hard rule. The faster you recover CAC, the less cash you tie up funding growth, which matters most for stores that are not sitting on a big cash cushion.

Blended CAC vs Paid CAC

Here is the distinction most CAC calculators blur, and the reason two stores can report the same CAC while one is thriving and one is quietly bleeding.

Blended CAC divides all of your spend by all of your new customers, including the ones who found you for free through SEO, email, word of mouth, or referrals. It is the flattering number because free organic customers pull the average down.

Paid CAC divides only your paid spend by only the customers who came from paid channels. It is the true marginal cost of buying a customer, which is the number that actually matters when you decide whether to increase your ad budget.

Worked example. Suppose you run three channels in a month:

• Google Ads: $2,000 spend, 40 new customers, so channel CAC is $50.
• Meta Ads: $1,000 spend, 10 new customers, so channel CAC is $100.
• Organic and SEO: $0 spend, 50 new customers, so channel CAC is $0.

Your blended CAC is total spend over total customers: (2,000 + 1,000 + 0) / (40 + 10 + 50) = 3,000 / 100 = $30. Your paid CAC is paid spend over paid customers only: (2,000 + 1,000) / (40 + 10) = 3,000 / 50 = $60.

The blended $30 looks great, but every extra customer you buy costs $60, not $30. If you plan an ad budget off the blended number you will overestimate how far it stretches. By channel mode in this tool shows both side by side and highlights the cheapest and priciest channels so you can shift budget toward what works.

How to Lower Customer Acquisition Cost

CAC is a fraction, so you lower it by spending less per customer or winning more customers from the same spend. The levers that work best for ecommerce:

• Lift conversion rate. The same traffic that already costs you money turns into more customers. A store that doubles its conversion rate halves the paid CAC with no extra ad spend.
• Grow cheaper organic channels. SEO, email, content, and referral programs win customers at a fraction of paid CAC. The more of your mix that comes from organic, the lower your blended CAC.
• Tighten targeting and creative. Cutting wasted ad impressions and improving your best-performing creative lowers cost per click and cost per customer on the paid side.
• Raise average order value. Bundles, volume discounts, free-shipping thresholds, and post-purchase upsells make each customer worth more, which improves the LTV:CAC ratio even if CAC itself does not move.

Every one of these feeds back into the ratio and the payback period, so a small win in two or three of them compounds quickly.

How to Use This Calculator

Simple mode is the fastest path to a number. Enter your total sales and marketing spend and your new customers to get CAC. Add your average customer LTV to unlock the LTV:CAC ratio and the health verdict, and add your monthly gross profit per customer to unlock the payback period. Every field recomputes live as you type.

By channel mode is for when you want to see where acquisition is efficient. Add a row per channel with its spend, its new customers, and whether it is paid or organic. The tool shows a per-channel CAC on every row, a blended CAC and a paid CAC side by side, a ranked table from cheapest to priciest, and a bar chart so the most efficient channel is obvious at a glance. Add your average LTV once and it grades the ratio against your blended CAC.

Everything runs in your browser. Nothing is uploaded, there is no signup, and there are no limits on how many times you calculate.

Frequently Asked Questions

What is customer acquisition cost (CAC)?

Customer acquisition cost is the average amount you spend on sales and marketing to win one new customer. It is total sales and marketing spend divided by the number of new customers that spend brought in over the same period.

What is the customer acquisition cost formula?

CAC = total sales and marketing spend / number of new customers acquired. Example: $5,000 of spend that won 100 new customers is a CAC of $50. Sales and marketing spend includes ad spend, tools, salaries, and agency or creative costs over the same period.

What is a good LTV:CAC ratio?

A ratio of 3:1 or higher is the common rule of thumb for a healthy, scalable store: each customer is worth at least three times what you pay to acquire them. Between 1:1 and 3:1 is thin, and below 1:1 means you lose money on acquisition.

What is the difference between blended CAC and paid CAC?

Blended CAC divides all spend by all new customers, including free organic ones, so it looks lower and can flatter your numbers. Paid CAC divides paid spend by customers from paid channels only, which is the true marginal cost of buying a customer.

What is the CAC payback period?

CAC payback period is how many months of gross profit from a customer it takes to earn back what you spent to acquire them: CAC / monthly gross profit per customer. Recovering CAC within about 12 months is commonly considered healthy.

How do I lower customer acquisition cost?

Improve conversion rate so the same traffic buys more, lean on cheaper organic channels like SEO, email, and referrals, tighten ad targeting and creative, and raise average order value so each customer is worth more against the same spend.

Is this customer acquisition cost calculator free?

Yes, it is 100% free, runs entirely in your browser, needs no signup, and has no limits on calculations.