CAC Calculator

Calculate blended and paid customer acquisition cost and the months of gross profit needed to pay each new customer back.

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Results will appear here once you enter your values.

Blended CAC vs Paid CAC

Customer acquisition cost is what you spend to win one new customer, but the answer changes depending on which costs and which customers you count. This calculator shows the two versions side by side so you can see the gap.

  • Blended CAC = all sales and marketing cost ÷ all new customers. With $30,000 of ads plus $20,000 of salaries, agency fees and tools, and 400 new customers from every source, blended CAC is 50,000 ÷ 400 =125.
  • Paid CAC = paid media spend ÷ customers attributed to paid channels. If ads drove 180 of those 400 customers, paid CAC is 30,000 ÷ 180 =166.67.
  • CAC payback = CAC ÷ (monthly ARPU × gross margin). At $40 a month and a 75% margin, each customer produces $30 of gross profit a month, so blended CAC pays back in 4.2 months and paid CAC in 5.6 months.

Blended CAC describes the efficiency of the whole go-to-market engine. Paid CAC isolates the channels you can scale up or down quickly, which is why it is the better number for setting ad budgets.

Why CAC Payback Matters

A low CAC is only good if customers generate enough profit to cover it quickly. Payback months turns CAC into a cash-flow question: how long until a new customer has repaid what it cost to win them? David Skok's SaaS Metrics 2.0 guidance treats recovering CAC in under 12 months as a healthy benchmark, and this tool labels under 12 months as fast, 12 to 24 as typical, and over 24 as slow.

  • Growth funding: every month of payback is a month your cash is tied up. Halving payback roughly halves the working capital growth needs.
  • Churn risk: if customers stay 20 months on average but payback is 24 months, the average customer never repays their acquisition cost.
  • Channel mix: when paid CAC is far above blended CAC, organic and referral channels are subsidising paid acquisition. Cutting them would raise your blended cost sharply.

Common Mistakes to Avoid

  • Counting only ad spend in blended CAC: salaries, commissions, agencies and software are real acquisition costs. Leaving them out can understate CAC by half or more in sales-led businesses.
  • Mismatched periods: spend and customers must cover the same window. If your sales cycle is 60 days, this month's customers were partly won by last month's spend, so use quarterly totals or lag the spend.
  • Counting existing customers: upgrades, reactivations and expansion revenue are not new customers. Including them lowers CAC artificially.
  • Trusting last-click attribution blindly: ad platforms often claim credit for customers who would have found you anyway, which makes paid CAC look lower than its true incremental cost.

If paid customers exceed all new customers, the tool warns you, because it almost always means the two numbers come from different date ranges or definitions.

Tips for Accurate CAC

  • Use a consistent period: a quarter smooths out lumpy months, such as a large conference or an annual software renewal.
  • Split by segment: enterprise and self-serve customers usually have very different CAC and ARPU, and averaging them hides both.
  • Use gross margin, not revenue, for payback: revenue-based payback flatters businesses with high delivery costs.
  • Track the trend: a rising paid CAC with a flat blended CAC is an early sign that ad channels are saturating.

Once you know CAC, use the customer lifetime value calculator to check your LTV:CAC ratio and decide how much more you can afford to spend.

Frequently Asked Questions

Common questions about the CAC Calculator

Divide the total cost of acquiring customers in a period by the number of new customers won in the same period. Blended CAC uses all sales and marketing costs and all new customers; paid CAC uses only paid media spend and the customers attributed to paid channels.

Sources & References

SaaS Metrics 2.0: A Guide to Measuring and Improving What Matters (David Skok, For Entrepreneurs)

Defines fully loaded CAC and the under-12-month CAC payback benchmark used for the payback bands.
→Source: For Entrepreneurs (David Skok)

Customer acquisition cost (Wikipedia)

Definition of customer acquisition cost as acquisition spend divided by customers acquired.
→Source: Wikipedia

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