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Blended CAC vs paid CAC: when each is the right metric

CAC depends on what you include. Learn paid-only CAC vs fully-loaded blended CAC, how to avoid mismatches, and how to connect CAC to payback.

Updated 2026-01-23

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Blended CAC Calculator
Example: $60k ads + $10k creative + $80k salaries + $5k tools; 120 customers

Why CAC has multiple definitions

CAC is only meaningful when the numerator and denominator are clearly defined. Paid CAC helps you optimize acquisition channels. Blended (fully-loaded) CAC helps you plan the business by allocating salaries and overhead to acquisition.

Two common CAC definitions

  • Paid CAC = variable paid acquisition spend / new paying customers.
  • Blended CAC = (variable spend + sales & marketing salaries + tools/overhead) / new paying customers.

How to connect CAC to payback

Payback months estimates how long it takes to recover CAC using monthly gross profit per customer: payback = CAC / (ARPA * gross margin).

Common mistakes (and how to avoid them)

  • Using leads/signups as the denominator (that's CPA/CPL; convert it to CAC using funnel conversion rates).
  • Comparing revenue-based LTV to fully-loaded CAC (mismatch). Prefer gross profit LTV or label definitions clearly.
  • Allocating fixed costs inconsistently across periods (creates fake CAC trend).

Practical reporting template

  • Paid CAC by channel/campaign (optimization).
  • Blended CAC overall and by segment (planning).
  • Payback months and LTV:CAC (health).

FAQ

Should I include brand marketing spend in CAC-
For planning (blended CAC), many teams include it if it contributes to acquisition at your stage. For channel optimization, keep the paid CAC numerator closer to variable costs tied to that channel.
Can blended CAC go down even if paid CAC rises-
Yes. If you scale acquisition volume, fixed costs per customer can fall. That can offset a rising paid CAC, which is why it helps to track both metrics.

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