What is blended CAC?
Blended customer acquisition cost (CAC) is total marketing spend divided by the number of new customers acquired in the same period. "Blended" means every channel is combined, paid and organic, with no attribution model. It shows what a brand actually pays, on average, to win each first-time customer.
Formula
Marketing spend ÷ new customers
Example
A hypothetical baby products brand spends $250,000 on marketing in a month and acquires 5,000 first-time customers. Blended CAC = $250,000 ÷ 5,000 = $50.
How to read it
Lower is better, but only relative to what a new customer is worth: a $50 CAC is fine if first-order contribution plus expected repeat purchases covers it comfortably. Because all marketing is in the numerator, retention and brand spend raise blended CAC even though they don't target new customers. Rising CAC during a scale-up is common; what matters is whether payback still works.
What moves it
- Paid media costs and audience saturation
- Creative performance and offer strength
- Word of mouth, press, and organic search that bring customers without spend
- Shifts of budget toward retention or brand campaigns
- Seasonality in ad auction prices
What to do when it's flagged
- Compare CAC to first-order contribution and repeat purchase rates to test payback
- Cut the campaigns with the highest cost per new customer
- Separate retention spend from acquisition spend to see the true acquisition cost
- Raise AOV or first-order margin so each new customer covers more of the cost
How Inflection tracks it
Inflection's KPI Monitor tracks blended CAC without a default flag; thresholds are set per client based on their margins and repeat purchase behavior.
Marketing spend comes from the QuickBooks P&L; new customer counts are entered manually until that input is connected.
Updated 2026-10-11. Example figures are hypothetical.