Natural CAC Scaling Threshold
Find the spend range where CAC barely rises, then map affordable growth
- Difficulty
- Advanced
- Time to result
- ~weeks to results
- Steps
- 5
- Confidence
- 92%
The Natural CAC Scaling Threshold is the spend range where a substantial budget increase produces only a small increase in customer acquisition cost. Establish the current spend and CAC, then raise spend in a controlled step and observe the marginal change. Menard's example moves from $30,000 to $40,000 per day while CAC rises from $40 to $40.50; he treats that pattern as evidence that the account may absorb much more budget near that cost level. The team then calculates what another one or two dollars of CAC would do to contribution margin and how much additional growth that trade could buy. Scaling proceeds through measured steps rather than a single leap. The method depends on an already sound offer and creative system, and it should be judged against blended business economics.
Origin
Extracted from The Foundr Podcast
Core principles
- 01Acquisition cost should be observed across spend increments
- 02A small CAC increase alongside a large spend increase signals room
- 03The business must price each additional unit of CAC
- 04Scaling is a controlled trade between cost and growth
How to run it
- 1
Establish the baseline
Record the current daily spend, acquisition cost, and contribution margin under reasonably stable conditions. Use enough data that a small movement is interpretable.
Pro tip Include blended business results alongside platform figures.
Watch out A noisy baseline makes a small CAC change meaningless.
- 2
Raise spend deliberately
Increase the budget by a material but controlled amount. Hold the offer and creative system sufficiently stable to observe the spending effect.
Watch out Do not combine the budget test with an untracked offer overhaul.
- 3
Measure marginal CAC
Compare the percentage increase in spend with the absolute and percentage increase in CAC. Look for a range where spend expands substantially while CAC moves only slightly.
Pro tip Menard describes this pattern as the account's natural CAC.
Watch out A single favourable fluctuation is not a stable threshold.
- 4
Price the next increment
Calculate how much additional CAC the business can absorb and how much growth that trade may unlock. Keep cash flow and contribution margin inside the decision.
Pro tip Model one or two dollars of added CAC before approving the next budget level.
Watch out Do not maximise spend at the expense of profitable growth.
- 5
Climb and recheck
Move to the next budget level, measure again, and continue only while the marginal economics remain acceptable. Stop when CAC deterioration consumes the available margin.
Watch out Past efficiency does not guarantee the same response at the next threshold.
In the wild
Menard gives a hypothetical account spending $30,000 per day at a $40 CAC. When spend rises to $40,000 and CAC reaches only $40.50, he reads the modest cost movement as a sign that the account may have substantial scaling room. The team would then model the growth available if CAC increased by another dollar or two.
→ The advertiser gets a measured budget path tied to affordable acquisition cost rather than an arbitrary scale target.
Common mistakes
Treating one observation as a law
The threshold should emerge as a repeatable account pattern, not a conclusion from one noisy day.
Ignoring the margin trade
A scalable CAC is useful only when the extra customers still create acceptable contribution margin and cash flow.
Is it for you?
Best for
It is best for mature ad accounts with stable offers, strong creative, and enough spend to read small CAC movements.
Not ideal for
It is not ideal for small or volatile accounts where ordinary noise overwhelms the effect of a budget increase.
From the transcript
“finding that finding that number is so key”
“can spend a lot more and CAC doesn't go up very much”
From the episode
561: $300M Worth of Facebook Ads Advice in 45 Minutes
Jordan Menard