Max CAC Calculator

What you could be paying to acquire a customer, based on your own cohort data and unit economics. Pick a tab below to switch lenses.

Based on Matt Putra's eightx Max CAC framework. Drop your cohort export and P&L numbers in to see where you are vs. where you could be.

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Variable Margin: 0.00%

Question: Should I lift my ad budget? Ad spend ÷ all new customers acquired. This is the marginal decision lens — it's what you should look at when deciding whether to spend more.

Customer Acquisition Cost

Current
ad spend ÷ customers
Ceiling
cohort × Variable Margin
Headroom
Period comparison Current / Prior / YoY / TTM
Current periodPrior periodYoYTTM
Ad spend ($)
New customers
CAC

Question: Is the marketing program paying for itself? Total marketing OPEX (ads + marketing payroll + SaaS + agency + everything you'd cut if you cut marketing) divided by new customers. This view is more conservative than ad-only.

Customer Acquisition Cost

Current
total mktg ÷ customers
Ceiling
same variable ceiling
Headroom
Period comparison Current / Prior / YoY / TTM
Current periodPrior periodYoYTTM
Total marketing ($)
New customers
CAC

Edit assumptions

Variable unit economics Variable Margin: 0.00%
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Pull these from your P&L. Variable Margin = Gross Margin − (Shipping + Payment + Influencer + Other). This is the margin per order AFTER fulfillment costs but BEFORE fixed costs like payroll, marketing, and overhead — it's the pool available to pay for acquisition.

Cohort grid 12 cohorts • Blank • TTM

Drop your customer cohort data here. Each row is a monthly cohort (when a customer first purchased). Each column is the AVERAGE CUMULATIVE SPEND per customer in that cohort by month X. Most ecommerce platforms (Shopify, BigCommerce) export this directly. Window selector at top filters which rows feed the ceiling. Switch to "Matt's demo" in the cohort dataset dropdown to see what populated data looks like.

CohortCustomers M0M1M2M3M4 M5M6M7M8M9 M10M11
Avg Spend (window)
Variable Margin contribution
Desired profit
Max CAC by month
Max CAC by break-even month — chart & range

CAC range — 5% steps from your target