averagecac.com

Two CACs that disagree by an order of magnitude

Blended CAC vs Paid CAC

Same company, same period, two CAC numbers that can differ by 10x. The reason isn't measurement noise. It's that the two formulas answer different questions, and most arguments about CAC happen because the two sides are talking about different metrics.

Blended CAC

Blended CAC = Total marketing spend ÷ Total net new customers

Every dollar of marketing spend divided by every new customer, regardless of how they got there. Includes content, brand, events, organic SEO, partnerships, paid media, free tier conversions, word of mouth. The denominator is a hard count of customers acquired in the period. No attribution model required.

When to use it: external reporting, board decks, cross-company comparison, when attribution is fuzzy or untrustworthy. Every CAC on our public-company pages is blended, computed from the SEC-disclosed S&M expense line.

Paid CAC

Paid CAC = Paid media spend ÷ Customers attributed to paid channels

Just paid media (Google, Meta, LinkedIn, programmatic, paid social) divided by customers attributable to paid channels under your attribution model. Excludes organic, content, brand, events, free tier, word of mouth. The denominator depends on the attribution window and model.

When to use it: optimising paid campaigns, evaluating channel mix, comparing CPC to CPA across platforms. Useful internally; almost useless for cross-company comparison because attribution windows and models vary so widely.

Why public companies report blended

The SEC requires public companies to disclose a single S&M expense line on the income statement. They cannot split out paid-channel spend from content, brand, sales team salaries, or commissions, even if they wanted to. So when a public company discloses customer growth, the implied CAC is always blended and fully-loaded by construction.

This is why our public-company pages publish blended CAC. We're not picking a formula. We're reading what's available. See the methodology page for the full pipeline.

When the two diverge wildly

For a company with mostly paid acquisition (early-stage DTC, performance marketing businesses), blended and paid CAC are close. For a company with strong organic, brand, partnership, or product-led growth, blended is often 2-5x paid because the blended denominator picks up free customers but the blended numerator still includes the brand and content investment that produced them.

A reasonable operator should track both, internally. A reasonable analyst should ask which one a counterparty is quoting before reacting to the number.

Common questions

Blended vs paid questions

Is paid CAC better than blended CAC?
Neither is better; they answer different questions. Paid CAC tells you whether your paid channels are efficient. Blended CAC tells you how much it costs to acquire a customer all-in. For internal channel optimisation, use paid. For external reporting and cross-company comparison, use blended.
Why does paid CAC differ from blended CAC?
Paid CAC only counts paid-media spend in the numerator and only paid-attributed customers in the denominator. Blended CAC counts everything: paid media, content, brand, events, sales salaries, commissions, free tier conversions, word of mouth. For a company with strong organic, blended is often 2-5x paid.
Which CAC do SaaS public companies report?
Public SaaS companies report a single S&M expense line in their 10-K (XBRL tag us-gaap:SellingAndMarketingExpense), which captures total fully-loaded blended marketing and sales spend. They don't separately disclose paid-channel CAC. So every CAC inferred from public filings is blended by construction.
How is paid CAC affected by attribution model changes?
Significantly. Switching from last-touch to multi-touch typically lowers paid CAC by 20-40% because credit is distributed across channels rather than concentrated on the final-touch channel. iOS 14.5+ privacy changes also reduced attributable paid customers, increasing paid CAC artificially. This is why paid CAC is hard to compare across companies or even within the same company over time.