How to Calculate CAC (Customer Acquisition Cost)

Short answer: CAC = total sales and marketing cost ÷ new customers acquired in the same period. The mistake most people make is only counting ad spend. True CAC includes salaries, software, agency fees, and creative costs — everything it took to win those customers.

CAC formula: total sales and marketing cost divided by number of new customers

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The CAC formula

Pick a consistent time period (monthly or quarterly) and count both the spend and the customers within that same window.

What to include in “total cost”

This is where most CAC calculations go wrong. A proper, fully loaded CAC includes:

A simple “ad spend ÷ customers” figure is really closer to CPA. Fully loaded CAC is almost always higher — and it’s the number investors and finance teams care about.

CAC vs CPA — what’s the difference?

Use CPA to optimise individual campaigns. Use CAC to evaluate whether your overall business model is sustainable. See CPA vs CAC for a deeper comparison.

Blended CAC vs paid CAC

Track both. Blended CAC tells you the real picture; paid CAC tells you whether your ad engine is working.

What makes a good CAC?

CAC only means something relative to customer lifetime value. The benchmark is the LTV:CAC ratio:

See the LTV:CAC ratio explained and CAC payback period. Run your own numbers with the LTV:CAC calculator.

Common mistakes

FAQ

How often should I calculate CAC?
Monthly for operational tracking, quarterly for strategic review. Watch the trend over time more than any single month’s number.

Should CAC include the cost of retaining customers?
No. CAC is strictly about acquisition. Retention and expansion costs are tracked separately and feed into LTV, not CAC.

Why is my CAC rising?
Common causes: rising CPCs, audience saturation, declining conversion rate, or scaling into lower-intent audiences. Diagnose which by checking CPC, conversion rate, and channel mix separately.

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