LTV:CAC Ratio Explained: The Single Most Important Indicator of Business Viability

The LTV:CAC ratio is the simplest and most powerful test of a subscription or recurring revenue business model. It answers one fundamental question: for every euro you spend to acquire a customer, how many euros do you get back over their lifetime?

What the Ratio Means

LTV:CAC = Customer Lifetime Value ÷ Customer Acquisition Cost

The 3:1 benchmark is not arbitrary. It assumes roughly 33% of LTV goes to sales and marketing, leaving 67% for R&D, G&A, and profit — a distribution that allows for sustainable growth.

Why Investors Care

Sophisticated investors don't just look at revenue growth — they look at capital efficiency. A company with LTV:CAC of 5:1 is a much better investment than one at 1.5:1, because every pound raised goes significantly further.

• Your unit economics work
• Scaling acquisition will not destroy margins
• The business is inherently profitable at the unit level

Common Mistakes

• Calculating LTV over too short a period: LTV estimates require a realistic customer lifetime, not just current months in business
• Ignoring gross margin in LTV: gross profit per customer matters, not gross revenue
• Mixing B2B and B2C segments: these often have very different LTV and CAC — segment separately

How to Improve Your Ratio

Improve LTV: reduce churn, add expansion revenue, improve gross margin Reduce CAC: improve conversion rates, invest in organic acquisition, optimise channel mix

Even a 20% improvement in each direction (LTV up 20%, CAC down 20%) turns a 2:1 ratio into a 3:1 ratio.

Calculate Your LTV:CAC Ratio

[👉 Use the LTV:CAC Ratio Calculator](/calculators/ltv-cac-ratio)

Enter your LTV and CAC to calculate your ratio, see where you stand against benchmarks, and model how changes affect your capital efficiency.