SaaS LTV & CAC efficiency calculator
Is your CAC eating all your profit? Calculate your LTV:CAC ratio and see if you can afford to scale.
- 1.Enter LTV
- 2.Add CAC
- 3.Read Ratio
- 4.Calculate Payback
- 5.Verify Sustainability
Key Takeaways
- →3:1 LTV:CAC is the industry standard — below that, growth burns cash
- →LTV = ARPU ÷ Monthly Churn — every 1% churn reduction dramatically increases LTV
- →CAC Payback under 12 months is healthy — over 18 months = cash flow risk
- →Above 5:1? You're under-investing in growth — hire more, spend more
What is SaaS LTV (customer lifetime value)?
LTV (Lifetime Value) is the total revenue you expect to earn from a customer over their entire relationship with your SaaS business.
Formula: LTV = ARPU × Average Customer Lifespan
Or with churn: LTV = ARPU ÷ Monthly Churn Rate
Example: $100/month ARPU ÷ 4% monthly churn = $2,500 LTV
LTV alone is meaningless — it matters in relation to CAC (Customer Acquisition Cost). The LTV:CAC ratio is the core unit economics metric for SaaS.
Ltv:cac ratio: the north star metric
| LTV:CAC | What It Means | Action |
|---|---|---|
| < 1:1 | Losing money on every customer | Stop spending, fix product |
| 1:1 - 2:1 | Breaking even at best | Reduce CAC or increase LTV |
| 3:1 | Healthy — industry standard | Scale cautiously |
| 5:1 | Efficient — scale aggressively | Invest in growth |
| > 10:1 | Under-investing in growth | Hire more, spend more |
Key Insight: 3:1 is the target for VC-backed SaaS. Below 3:1, growth burns cash. Above 5:1, you're leaving growth on the table.
SaaS LTV benchmarks by segment (2025)
| Segment | Average LTV | Top Performers |
|---|---|---|
| SMB (<$1K ACV) | $500-2,000 | $3,000+ |
| Mid-Market ($1-10K ACV) | $5,000-25,000 | $40,000+ |
| Enterprise ($10K+ ACV) | $50,000-200,000 | $500,000+ |
Why Enterprise wins: Longer contracts, lower churn, more upsell opportunity.
LTV calculation methods
| Method | Formula | Best For |
|---|---|---|
| Simple | ARPU × Months | Quick estimates |
| Churn-Based | ARPU ÷ Churn Rate | Monthly subscribers |
| Cohort | Sum of revenue per cohort over time | Accurate historical |
| Predictive | ML models using engagement data | Best accuracy |
Recommendation: Use cohort analysis for established products. Use churn-based for early-stage estimates.
CAC payback: when do you break even?
| Payback Period | Assessment |
|---|---|
| < 6 months | Excellent — scale fast |
| 6-12 months | Healthy — VC expectation |
| 12-18 months | Acceptable for enterprise |
| > 18 months | Cash flow risk |
Formula: CAC Payback = CAC ÷ (Monthly ARPU × Gross Margin)
Example: $1,200 CAC ÷ ($100 × 80%) = 15 months payback
Why your ltv:cac is below 3:1 (top 5 reasons)
1. high churn
Every percentage point of monthly churn destroys LTV. A 5% monthly churn = 20-month average lifespan. A 2% churn = 50-month lifespan.
2. CAC too high
If you're paying $500+ to acquire $50/month customers, the math never works. Focus on lower-cost channels (organic, referrals).
3. no expansion revenue
LTV is capped without upsells. Product-led growth with natural expansion (seats, usage) increases LTV without additional CAC.
4. wrong customer segment
SMB customers churn 2-3x faster than enterprise. If unit economics don't work, move upmarket.
5. pricing too low
If competitors charge 2-3x more, you're leaving LTV on the table. Price on value, not cost.
How to improve ltv:cac
| Strategy | Impact on LTV:CAC | Difficulty |
|---|---|---|
| Reduce churn (onboarding, CS) | +20-50% LTV | Medium |
| Increase pricing | +10-30% LTV | Low |
| Add expansion revenue | +15-40% LTV | Medium |
| Improve CAC (organic, PLG) | -30-50% CAC | High |
| Move upmarket | +50-100% LTV | High |
Frequently Asked Questions
FAQ
What is a "good" ltv:cac ratio for SaaS?
3:1 is the industry standard. 5:1+ is excellent. Below 3:1 signals a problem.
How do i calculate LTV if i'm pre-revenue?
Use assumptions: estimated ARPU × estimated lifespan (based on industry benchmarks). Refine as you get data.
Is ltv:cac the same as ROI?
Similar concept. LTV:CAC measures customer-level economics. ROI measures overall return on investment.
Should i use gross margin in LTV calculations?
Yes. Gross-margin-adjusted LTV (LTV × Gross Margin %) gives a more accurate picture of profitability.
What churn rate should i assume for LTV?
Use your actual churn. If early-stage, assume 5-8% monthly for SMB, 2-3% for mid-market, <1% for enterprise.
How does pricing model affect LTV?
Usage-based and seat-based pricing increase LTV through natural expansion. Flat-rate pricing caps LTV.
What's the relationship between NDR and LTV?
NDR > 100% increases LTV beyond the initial contract. A 120% NDR effectively multiplies LTV by 1.2x per year.
Do vcs use ltv:cac for investment decisions?
Absolutely. It's one of the top 3 metrics (along with NDR and growth rate) for SaaS investing.