The most common error is calculating CAC as ad spend divided by new customers. That's channel CAC, and it understates the real figure by excluding salaries, tooling, creative production, and agency fees.
Blended CAC includes everything spent on acquisition across every channel. It's the number that matters for business decisions, because it's the number that actually leaves your bank account.
CAC on its own is meaningless without context. A $900 CAC is excellent for a product with $600 monthly revenue and terrible for one with a $40 order value and no repeat purchase.
Formula
Blended CAC = (Ad Spend + Marketing Salaries + Tools + Agency Fees + Creative Costs) ÷ New Customers Acquired
Pair it with payback period — CAC ÷ monthly contribution per customer — which is what determines how fast you can reinvest.
Why CAC matters
CAC payback period, more than CAC itself, determines how fast a business can grow without external funding. A company recovering CAC in four months can reinvest three times a year; one at eighteen months cannot self-fund growth at all.
Why LTV:CAC can mislead
Two companies both have a 3:1 LTV:CAC ratio. The first recovers CAC in 5 months; the second takes 22 months because its LTV is spread over four years. The ratios are identical and the businesses are completely different — the second needs far more working capital to grow at the same rate. Always pair the ratio with payback period.
Benchmarks
- Healthy B2B SaaS payback
- under 12 months
- Healthy DTC payback
- under 3 months
- Commonly cited LTV:CAC target
- 3:1 or better
Ranges drawn from Digital Squad client accounts and published industry data. Treat them as orientation, not targets — your category may differ substantially.
Common mistakes
Excluding salaries and agency fees
The most common error, and it usually understates real CAC by 30–50%. If a cost exists to acquire customers, it belongs in CAC.
Counting reactivated customers as new
A lapsed customer returning is retention, not acquisition. Mixing them flatters CAC and hides a genuine acquisition problem.
Ignoring the lag between spend and conversion
In long cycles, this month's customers came from earlier spend. Dividing this month's spend by this month's customers produces noise, especially when spend is changing.
Using LTV:CAC without payback
The ratio ignores time entirely. A 3:1 ratio recovered over four years is a cash-flow problem regardless of how healthy it looks.
Where we work on this