Home / Guides / Customer acquisition cost: match spending to new customers

Customer acquisition cost: match spending to new customers

Published by Navon Ventures S.A.S · October 27, 2026

Customer acquisition cost, or CAC, divides included acquisition spending by new customers. The answer is money per customer, not a conversion percentage. Matching both sides to the same business scope and measurement window makes the result more interpretable than a ratio of unrelated totals.

Which inputs to use

Sales and marketing costs

Decide whether to include campaign spend alone or fuller costs such as sales payroll and tools. Record that choice for future comparisons.

New customers

Count newly acquired customers for the corresponding period or cohort. Leads, repeat orders and total website visitors are different denominators.

Formula and worked example

Acquisition costs ÷ new customers

Acquisition costs of $6,000 for 40 new customers produce 6,000 ÷ 40 = $150 per customer. If that spending corresponds to only 30 new customers, the result becomes $200. The change reflects the denominator but does not explain why acquisition performance changed.

Common interpretation mistakes

A short window may count costs now and conversions later, making the ratio unstable. The reverse occurs when customers from earlier spending are credited to a later period. Campaign-only cost should not be described as fully loaded CAC if salaries, agency fees or tools have deliberately been left out.

Assumptions and limits

A positive customer count is required; zero new customers cannot produce a finite cost per acquired customer through division. The tool does not deduplicate records or establish payback time. Compare it cautiously with lifetime gross-profit value using aligned customer cohorts and costs, rather than assuming a particular ratio guarantees viability.

You can also explore Customer lifetime value.