Every founder knows CAC and LTV matter. Very few are calculating them in a way that's actually useful for decisions. Here's where the thinking usually breaks down — and how to fix it.
Most brands obsess over lowering CAC. That's reasonable on the surface, but CAC in isolation tells you almost nothing. A ₹500 CAC is great if LTV is ₹3,000. It's terrible if LTV is ₹600. The question is never "how low is our CAC?" — it's "how fast does our CAC pay back, and what does the customer do after?"
Optimising for CAC without understanding contribution margin and payback period is how brands scale themselves into a cash flow crisis.
When founders say LTV, they usually mean a projected average over 12–24 months, often based on overall average order value × purchase frequency. The problem: this blends your best customers with your one-time buyers and gives you a number that's hard to act on.
More useful: calculate LTV by cohort. Group customers by acquisition month, then track what each cohort spends at 30, 60, 90, 180, and 365 days. This tells you whether newer customers are better or worse than older ones — which is the signal you actually need to make budget decisions.
The metric that connects CAC and LTV in a usable way is payback period: how many months does it take for a customer's contribution margin to recover the cost of acquiring them?
One more common error: calculating LTV on revenue instead of contribution margin. If your AOV is ₹1,200 but after COGS, shipping, payment gateway fees, and returns your contribution per order is ₹400, then your LTV on a 3-purchase customer is ₹1,200 — not ₹3,600. Basing CAC targets on revenue LTV means you're structurally losing money on every customer you acquire.
Build a simple cohort table in a spreadsheet. For each acquisition month, track cumulative revenue and cumulative contribution margin at each time interval. Set a target payback period based on your cash runway. Then set your CAC ceiling accordingly — and hold to it even when it means not scaling as fast as you'd like.
The brands that build durable growth aren't the ones with the lowest CAC. They're the ones who know exactly what a customer is worth and spend accordingly.
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