LTV:CAC is the single most important metric for subscription businesses. It tells you whether you're building a profitable company or just buying revenue at a loss.
What Is LTV:CAC Ratio?
LTV:CAC = Customer Lifetime Value / Customer Acquisition Cost
It measures how much value you generate from a customer compared to what you spend to acquire them.
Example:
- LTV: $3,000
- CAC: $500
- LTV:CAC: 6:1
For every $1 spent on acquisition, you generate $6 in value. That's healthy.
The LTV:CAC Formulas
Calculating LTV (Lifetime Value)
Simple LTV: LTV = ARPU / Churn Rate
Where:
- ARPU = Average Revenue Per User (monthly)
- Churn Rate = Monthly customer churn percentage
Example:
- ARPU: $100/month
- Monthly churn: 2%
- LTV: $100 / 0.02 = $5,000
LTV with Gross Margin: LTV = (ARPU × Gross Margin) / Churn Rate
Include gross margin for a more accurate picture of profit:
- ARPU: $100/month
- Gross margin: 80%
- Monthly churn: 2%
- LTV: ($100 × 0.80) / 0.02 = $4,000
Calculating CAC (Customer Acquisition Cost)
Basic CAC: CAC = Total Acquisition Spend / New Customers
What's included in acquisition spend:
- Marketing spend (ads, content, events)
- Sales salaries and commissions
- Sales tools and software
- Agency fees
- Marketing team salaries
Example:
- Monthly marketing spend: $50,000
- Sales team cost: $30,000
- New customers acquired: 40
- CAC: $80,000 / 40 = $2,000
Putting It Together
LTV: $4,000 CAC: $2,000 LTV:CAC: 2:1
This is below the healthy benchmark—we need to either increase LTV or decrease CAC.
LTV:CAC Benchmarks
By Industry
| Business Type | Healthy LTV:CAC | |---------------|-----------------| | B2B SaaS | 3:1 to 5:1 | | B2C Subscription | 3:1 to 4:1 | | E-commerce | 3:1 to 4:1 | | Marketplace | 2:1 to 3:1 |
What the Ratios Mean
| LTV:CAC | Interpretation | |---------|----------------| | Below 1:1 | Losing money on every customer. Unsustainable. | | 1:1 to 2:1 | Breaking even to slight profit. Needs improvement. | | 3:1 | Healthy. Standard SaaS benchmark. | | 4:1 to 5:1 | Strong unit economics. Room for growth investment. | | Above 5:1 | Excellent, but maybe underinvesting in growth? |
The "3:1 Rule"
The venture capital benchmark for healthy SaaS is LTV:CAC ≥ 3:1.
Why 3:1?
- 1x covers acquisition cost
- 1x covers operational costs to serve the customer
- 1x provides profit margin
Below 3:1, you're probably not building a sustainable business without major changes.
CAC Payback Period
LTV:CAC tells you the total relationship value. CAC Payback tells you how fast you recover the acquisition cost.
CAC Payback Formula: CAC Payback (months) = CAC / (ARPU × Gross Margin)
Example:
- CAC: $2,000
- ARPU: $100/month
- Gross margin: 80%
- CAC Payback: $2,000 / ($100 × 0.80) = 25 months
Payback Benchmarks
| Payback Period | Interpretation | |----------------|----------------| | Less than 12 months | Excellent. Efficient acquisition. | | 12-18 months | Good. Standard for B2B SaaS. | | 18-24 months | Acceptable for enterprise. | | More than 24 months | Concerning. High capital intensity. |
Improving LTV:CAC
Increasing LTV
1. Reduce Churn Every 1% reduction in monthly churn dramatically increases LTV.
2% → 1% churn: LTV doubles.
Focus on:
- Better onboarding
- Proactive customer success
- Feature adoption tracking
- Exit surveys and intervention
2. Increase ARPU More revenue per customer = higher LTV.
Strategies:
- Price increases (often underpriced)
- Upselling to higher tiers
- Add-on products/features
- Usage-based pricing components
3. Expand Revenue Net revenue retention above 100% means existing customers grow.
Tactics:
- Seat-based expansion
- Usage growth incentives
- Premium feature upgrades
- Cross-sell additional products
Decreasing CAC
1. Improve Conversion Rates Same spend, more customers = lower CAC.
Optimize:
- Landing page conversion
- Free trial to paid conversion
- Sales demo effectiveness
- Pricing page clarity
2. Focus on High-Intent Channels Some channels have lower CAC than others.
Typically lower CAC:
- SEO/organic content
- Referrals
- Product-led growth
- Existing customer expansion
Typically higher CAC:
- Paid social ads
- Outbound sales
- Events/conferences
3. Shorten Sales Cycles Faster close = less sales cost per deal.
Methods:
- Better qualification (focus on ready buyers)
- Simplified pricing
- Self-serve options
- Automated follow-up
4. Leverage Word of Mouth Referral customers often have near-zero CAC.
Build referral programs and focus on customer satisfaction to drive organic growth.
Segmenting LTV:CAC
Aggregate LTV:CAC hides important patterns. Calculate it by:
By Customer Segment
| Segment | LTV | CAC | LTV:CAC | |---------|-----|-----|---------| | Enterprise | $50,000 | $15,000 | 3.3:1 | | Mid-Market | $12,000 | $3,000 | 4:1 | | SMB | $2,000 | $500 | 4:1 | | Self-Serve | $800 | $100 | 8:1 |
This reveals: Self-serve is most efficient. Maybe invest more there.
By Acquisition Channel
| Channel | LTV | CAC | LTV:CAC | |---------|-----|-----|---------| | Organic Search | $4,000 | $200 | 20:1 | | Referrals | $4,500 | $150 | 30:1 | | Paid Ads | $3,000 | $1,500 | 2:1 | | Outbound Sales | $6,000 | $4,000 | 1.5:1 |
This reveals: Paid ads and outbound may need optimization or cutting.
By Cohort
Track LTV:CAC over time to see if unit economics are improving:
| Cohort | LTV:CAC | |--------|---------| | Q1 2024 | 2.5:1 | | Q2 2024 | 2.8:1 | | Q3 2024 | 3.2:1 | | Q4 2024 | 3.5:1 |
Improving! Changes are working.
Common LTV:CAC Mistakes
1. Using Revenue Instead of Gross Profit
LTV should account for cost to serve. Use gross margin in the calculation.
2. Excluding All Acquisition Costs
CAC should include all sales and marketing spend, including salaries. Many startups undercount.
3. Ignoring Time Value of Money
$3,000 received over 5 years isn't worth $3,000 today. For venture-backed startups, this matters less due to access to capital.
4. Not Segmenting
Aggregate numbers hide unprofitable segments. Always break down by customer type and channel.
5. Short-Term Measurement
LTV takes time to observe. Use projected LTV based on early retention patterns, but validate over time.
LTV:CAC for Fundraising
What Investors Want to See
Seed Stage:
- Some evidence of LTV:CAC potential
- Early cohort retention data
- Hypothesis on improving unit economics
Series A:
- LTV:CAC above 3:1 (or clear path)
- 12-18 month payback period
- Improving trend over cohorts
Series B+:
- Proven LTV:CAC above 3:1
- Under 12 month payback
- Predictable by segment and channel
Presenting LTV:CAC
Show:
- Current LTV:CAC with methodology
- Trend over last 4+ quarters
- Breakdown by segment/channel
- Path to improvement (if needed)
Using Our Free Calculator
Our Unit Economics Calculator calculates:
- LTV from ARPU and churn
- CAC from spend and customers
- LTV:CAC ratio with benchmarks
- CAC Payback in months
No signup. Instant results. Model different scenarios.
Quick Reference
Formulas
| Metric | Formula | |--------|---------| | LTV | ARPU × Gross Margin / Churn Rate | | CAC | Total Acquisition Spend / New Customers | | LTV:CAC | LTV / CAC | | Payback | CAC / (ARPU × Gross Margin) |
Benchmarks
| Metric | Healthy Target | |--------|----------------| | LTV:CAC | ≥ 3:1 | | CAC Payback | ≤ 12 months | | Net Revenue Retention | ≥ 100% | | Logo Churn | ≤ 5% annual |
Conclusion
LTV:CAC isn't just a metric—it's the fundamental equation of your business sustainability.
Key principles:
- Measure accurately - Include all costs, use gross margin
- Benchmark properly - 3:1 is the floor, not the ceiling
- Segment ruthlessly - Aggregate hides problems
- Improve systematically - Work both LTV and CAC levers
- Track over time - Cohort trends reveal the truth
Ready to calculate your unit economics? Use our free Unit Economics Calculator.