LTV:CAC Ratio

Quick Definition

The ratio comparing customer lifetime value to acquisition cost, indicating whether your unit economics support sustainable growth.

What is LTV:CAC Ratio?

LTV:CAC ratio compares how much a customer is worth over their lifetime to how much it costs to acquire them. It's the single most important unit economics metric for subscription businesses.

A ratio of 3:1 means every dollar spent on acquisition generates three dollars in customer value. This is the minimum benchmark for a sustainable SaaS business.

What's a Good LTV:CAC Ratio?

Below 1:1 means you're losing money on every customer. Between 1:1 and 3:1 suggests unsustainable economics. 3:1 to 5:1 is the sweet spot for most companies. Above 5:1 might mean you're underinvesting in growth.

The ideal ratio depends on your stage. Early startups might accept lower ratios to gain market share. Mature companies should optimize toward 3:1 or higher.

How to Calculate LTV:CAC Ratio Step by Step

Step 1: Calculate your LTV. Use the gross-margin-adjusted formula for accuracy (see the full LTV walkthrough).

• ARPU: $250/month
• Gross margin: 80%
• Monthly churn: 3%
• LTV = ($250 × 0.80) ÷ 0.03 = $6,667

Step 2: Calculate your fully-loaded CAC. Include all sales and marketing costs (see the full CAC walkthrough).

• Total quarterly S&M spend: $135,000
• New customers acquired: 45
• CAC = $135,000 ÷ 45 = $3,000

Step 3: Divide LTV by CAC.

• LTV:CAC = $6,667 ÷ $3,000 = 2.2:1 ⚠️

Below the 3:1 benchmark. You're spending too much to acquire customers relative to their value.

Step 4: Diagnose the problem. Is LTV too low or CAC too high?

• If churn is above 5% monthly → LTV problem. Fix retention first
• If CAC payback exceeds 18 months → CAC problem. Optimize channels
• If gross margin is below 70% → Margin problem. Reduce COGS
• If ARPU is below competitors → Pricing problem. Test price increases

Step 5: Segment by channel and customer type. Your blended ratio might hide that inbound is 5:1 while outbound is 1.5:1. Or that enterprise customers are 8:1 while SMB is 1.8:1. These insights drive resource allocation.

Common mistakes founders make:

• Using revenue-based LTV instead of gross-profit-based LTV (overstates the ratio)
• Undercounting CAC by excluding salaries and tools
• Comparing against benchmarks from different industries (ecommerce LTV:CAC norms differ from SaaS)
• Not recalculating regularly — both LTV and CAC change as you scale and evolve

Improving LTV:CAC

Two levers: increase LTV or decrease CAC. Reduce churn, raise prices, drive expansion revenue to boost LTV. Improve conversion rates, optimize channels, reduce sales cycle to lower CAC.

Formula LTV:CAC Ratio = Customer Lifetime Value ÷ Customer Acquisition Cost

Where LTV = (ARPU × Gross Margin) ÷ Churn Rate

Example
Your metrics:

• ARPU: $200/month
• Gross margin: 80%
• Monthly churn: 2%
• CAC: $2,000

LTV = ($200 × 0.80) ÷ 0.02 = $8,000

LTV:CAC = $8,000 ÷ $2,000 = 4:1

Healthy ratio indicating efficient growth. Each acquisition dollar returns four dollars in customer value.