CAC Payback Calculator
CAC Payback Period measures how many months it takes to recover your customer acquisition cost through gross profit. Shorter payback periods mean faster return on marketing investment and better capital efficiency. This metric is critical for cash flow planning.
How to Calculate
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CAC Payback = CAC / (ARPU × Gross Margin)
Example:
CAC = $600
ARPU = $100/month
Gross Margin = 80%
Payback = $600 / ($100 × 0.80) = 7.5 months
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Industry Benchmarks
| Payback Period | Health | Implications |
|---|---|---|
| <6 months | Excellent | Fast capital recovery |
| 6-12 months | Good | Standard for B2B SaaS |
| 12-18 months | Acceptable | May need financing |
| >18 months | Concerning | Cash flow strain |
Interpreting Your Results
Payback period directly impacts growth velocity. Shorter payback means you can reinvest in growth faster. If payback exceeds 18 months, focus on reducing CAC or increasing ARPU before scaling acquisition.
Why This Metric Matters
Understanding CAC Payback helps you:
- Make data-driven business decisions with confidence
- Benchmark against industry standards and competitors
- Identify areas for improvement in your business model
- Communicate performance clearly to stakeholders and investors
- Set realistic goals and track progress over time
Best Practices for Accurate Measurement
1. Use consistent time periods: Compare month-over-month or quarter-over-quarter consistently 2. Include all relevant data: Ensure you capture all revenue sources and costs 3. Track cohorts separately: Analyze metrics by customer segment and acquisition date 4. Monitor trends: Single snapshots are less valuable than trends over time 5. Automate tracking: Use analytics tools to ensure consistent, accurate measurement
Every Metric From These Inputs
100 customers at $49 with 3% monthly churn and $200 CAC:
| Metric | Value | Formula |
|---|---|---|
| MRR | $4,900 | customers × ARPU |
| ARR | $58,800 | MRR × 12 |
| Annual churn | 30.6% | 1 − (1 − monthly)¹² |
| Average lifetime | 33.3 months | 1 ÷ monthly churn |
| LTV | $1,633 | ARPU ÷ monthly churn |
| LTV : CAC | 8.2:1 | LTV ÷ CAC |
| CAC payback | 4.1 months | CAC ÷ ARPU |
What Good Looks Like
| Metric | Healthy | Concerning |
|---|---|---|
| Monthly churn (SMB) | Under 3% | Above 5% |
| Monthly churn (enterprise) | Under 1% | Above 2% |
| LTV : CAC | 3:1 or better | Below 1:1 |
| CAC payback | Under 12 months | Above 18 |
| Net revenue retention | Above 100% | Below 90% |
The Metric This Set Omits
Net revenue retention — expansion revenue minus churn and contraction, from existing customers only. Above 100% means the business grows without acquiring anyone, which is the single strongest signal in SaaS and the one that most affects valuation. It cannot be derived from the inputs above because it needs upgrade and downgrade data.