A customer can be profitable over a year and still be difficult to finance if it takes six months to recover acquisition cost.
That is why CAC payback period matters.
What is payback period?
Customer payback period is the time required for cumulative contribution from a customer or cohort to recover the acquisition cost.
Example:
CAC = ₹800
First-order contribution = ₹500
The customer has ₹300 left to recover.
If a second order generates ₹400 of contribution after 45 days, the customer reaches payback around that point.
Why revenue is the wrong measure
If a customer spends ₹2,000, that does not mean the business has ₹2,000 available to recover CAC.
You need to subtract variable costs.
Payback should therefore be based on contribution.
Build a cohort view
For each acquisition cohort, track:
- Day 0 contribution
- Day 30 cumulative contribution
- Day 60
- Day 90
- Day 180
Then compare cumulative contribution with CAC.
You may find:
- Paid social reaches payback at 120 days.
- Referral reaches payback at 20 days.
- Affiliate reaches payback at 60 days.
Those are hypothetical examples, but they show why channel comparison should go beyond CAC. Use our Shopify LTV & Cohort Analyzer to inspect your real order cohorts.
Discounts can change payback
A heavily discounted first order may have low contribution.
If the customer repeats quickly, the cohort may still pay back well.
If discounted customers do not repeat, the payback period may become very long or never be reached.
Use payback for growth decisions
A channel with a lower CAC is not automatically better.
Ask:
- How quickly does it recover CAC?
- How predictable is the repeat contribution?
- How much working capital is required?
- How sensitive is payback to discounting?
This turns acquisition reporting into an operating decision.
The goal is not simply to acquire customers cheaply.
It is to recover the investment predictably.