Two metrics show whether spending produces profit: return on investment and the ratio of customer lifetime value to acquisition cost.
ROI
ROI equals gain minus cost, divided by cost. Spending $25,000 and receiving $38,000 produces a 52% ROI. Compare projects on annualized ROI when time horizons differ.
LTV and CAC
Customer lifetime value is the profit you expect from a customer over the relationship. Customer acquisition cost is what you spend to win one. A ratio of 3:1 or better is a common benchmark, and payback within 12 months is healthy for many businesses.
Improving the ratio
Raise retention, increase average order value, upsell, reduce acquisition cost through better channels and focus on customers with higher margin. Measure by cohort to avoid misleading averages.
Try the numbers
Use our ROI Calculator to see this in practice. With its default example (Amount invested: $25,000; Final value / revenue: $38,000; Years: 3), it shows roi: 52%. Adjust the inputs to match your situation.
Key takeaways
- ROI = (gain − cost) ÷ cost.
- Aim for LTV:CAC of 3:1 or better.
- Measure by cohort for accuracy.
This article is for general education and is not personalized financial, tax or legal advice. Rules and limits change; confirm current figures with official sources such as IRS.gov, SSA.gov and StudentAid.gov, or consult a qualified professional. © 2026 FinanzCalc.