GlossaryFinance & Governance

Blended CAC vs Incremental CAC

Also known as: CAC Arbitrage

Blended CAC is Total Spend / Total New Customers. Incremental CAC is Total Spend / *Net New Paying* Customers generated by that spend. Blended CAC averages strictly paid performance with free organic traffic, often masking the inefficiency of paid channels.

The Short Version

Blended is a company metric. Incremental is a marketing metric.

Prerequisites

The Scaling Ceiling

You scale based on a $40 Blended CAC. But your Incremental CAC is $120.

As you spend more, 'organic' stays flat, so Blended CAC rapidly converges towards the expensive Incremental CAC, destroying profitability.

How it works

1

Blended CAC = Total Spend / Total Customers

2

Incremental CAC = Total Spend / (Total Customers - Baseline Customers)

3

Compare the delta to see how much 'Organic Subsidy' you are relying on

Common Misconceptions

Setting paid media targets based on Blended CAC

Denying that diminishing returns exist because Blended CAC looks stable

Failing to separate paid impact from brand momentum

In SpendSignal

SpendSignal displays both metrics side-by-side. We alert you when the gap between Blended and Incremental CAC becomes dangerous.

Frequently Asked Questions

QWhen should I use Blended?

Use Blended for overall business financial planning (P&L). Use Incremental for making ad budget decisions.

Ask about ROAS, Attribution, or Budget...