LTV:CAC is the single most-cited subscription health metric, and for good reason — it captures the entire economics of the business in one number. A customer worth 3x what they cost to acquire is a sustainable business. A customer worth 1x what they cost is no business at all.
The ratio explained
LTV:CAC = Customer Lifetime Value ÷ Customer Acquisition Cost
If LTV is $600 and CAC is $200, your LTV:CAC is 3:1 — a customer is worth 3x what you paid to acquire them. That 3x covers acquisition cost plus your operating margin plus your growth budget plus profit.
The standard benchmarks
- LTV:CAC ≥ 3:1 — healthy. Acquisition is paying for itself with margin for everything else.
- LTV:CAC ≈ 2:1 — tight. Working but limited room for operating cost or growth investment.
- LTV:CAC ≈ 1:1 — break-even on acquisition. You are buying revenue at cost.
- LTV:CAC ≥ 5:1 — possibly under-investing in growth. You could likely acquire more aggressively and still be healthy.
These are heuristics, not laws. The right ratio depends on margin, payback period, and growth stage.
Where LTV:CAC misleads
- LTV estimates are usually optimistic. Most LTV models assume current retention rates hold forever. They rarely do. If you are forecasting LTV from short cohort data, the ratio will look better than it really is.
- CAC is often understated. Salaries, tools, and content production frequently get left out. Real CAC is usually 20–50% higher than the "ads only" number.
- Aggregate ratios hide segment problems. A 3:1 average can hide a 1:1 paid social cohort and a 6:1 organic cohort. The aggregate is healthy; one channel is destroying value.
- Time horizon matters. 18-month LTV vs. 36-month LTV give very different ratios. Pick a horizon and stick with it.
How to improve LTV:CAC
Two halves of the ratio, two directions to work:
- Raise LTV — better retention, higher AOV, longer tenure. See customer lifetime value.
- Lower CAC — better conversion, more organic acquisition, tighter targeting. See lower customer acquisition cost.
Most subscription businesses get more leverage from raising LTV than lowering CAC — retention compounds across every cycle, while CAC reductions are bounded.
Payback period: the companion metric
LTV:CAC tells you whether acquisition is profitable. Payback period tells you how quickly. A 3:1 ratio with 36-month payback is harder to run than the same ratio with 12-month payback because cash flow tightens. Most healthy subscription businesses target 6–12 month payback alongside their LTV:CAC.