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Series A Customer Acquisition Cost Estimator

This Series A Customer Acquisition Cost Estimator calculates blended and paid CAC from sales and marketing spending and newly acquired customers. It helps growth teams compare acquisition efficiency across channels and reporting periods.

Enter spending and customer counts from the same period. Paid CAC excludes organic customers from the denominator, while blended CAC uses all new customers. The sales-and-marketing percentage of new annual recurring revenue adds context for subscription businesses.

Inputs

USD
USD/year
Result
—
Blended customer acquisition cost
Blended CAC—
Paid CAC
Organic customers—
S&M as % of new ARR—

1. Enter spend
Include the sales and marketing costs attributable to the acquisition period.

2. Enter total customers
Count all new customers acquired in that same period.

3. Identify paid customers
Enter the subset attributed to paid or sales-assisted efforts.

4. Add new ARR
Optionally enter annual recurring revenue created by the cohort.

5. Compare CAC views
Use blended CAC for company-wide planning and paid CAC for channel efficiency.

Blended CAC = Sales and marketing spend / Total new customers Paid CAC = Sales and marketing spend / Paid-attributed customers S&M share of new ARR = Spend / New ARR

Customer counts and spending must cover the same period. Attribution rules materially affect paid CAC, so use one method consistently.

What the result means

CAC is the average acquisition spending required for each new customer under the selected attribution basis.

This simplified estimate does not allocate overhead or account for the delay between spending and conversion.

Given

  • $600,000 spend
  • 300 total new customers
  • 220 paid-attributed customers
  • $1,800,000 new ARR

Calculation

Blended CAC = $600,000 / 300 = $2,000. Paid CAC = $600,000 / 220 = $2,727.27.

Result

Blended CAC = $2,000; paid CAC = $2,727.27.

Organic acquisition lowers blended CAC relative to the paid-only result.

Should sales salaries be included?

Include them when the sales team directly supports acquisition and your CAC policy treats those costs as acquisition spending.

How should shared marketing costs be handled?

Allocate them using a consistent rule, such as campaign usage or team time, and document that rule.

Why is paid CAC higher than blended CAC?

Paid CAC divides spending by only paid-attributed customers, while blended CAC includes organic customers in the denominator.

Can leads be used instead of customers?

Not for customer CAC. Using leads produces cost per lead, which measures a different stage of the funnel.

Which CAC should be compared with LTV?

Use a CAC definition that matches the customer segment and acquisition channel represented by the LTV estimate.