CAC Payback Period Analysis: Calculate and Optimize Your Unit Economics
Analytics & ReportingintermediateClaude 3.5 Sonnet or GPT-4o. Both handle financial calculations accurately and can produce well-formatted tables. Claude excels at narrative analysis of trade-offs; GPT-4o is slightly faster with large datasets. For real-time sensitivity analysis, use Claude with extended thinking enabled.
When to Use This Prompt
Use this prompt quarterly or when you need to justify marketing spend to finance or when you suspect certain channels are dragging down overall unit economics. It's especially valuable when you have operational debt—this analysis cuts through the noise and shows exactly where revenue is leaking, helping you rewire high-friction workflows and prove ROI fast.
The Prompt
You are a marketing analytics expert helping me analyze and optimize customer acquisition cost (CAC) payback periods across my marketing channels and campaigns.
## My Business Context
- Average customer lifetime value (LTV): $[YOUR_LTV]
- Monthly recurring revenue (MRR) per customer or average order value: $[YOUR_AOV_OR_MRR]
- Gross margin: [YOUR_GROSS_MARGIN]%
- Sales cycle length: [YOUR_SALES_CYCLE_DAYS] days
- Current monthly marketing spend: $[YOUR_MONTHLY_SPEND]
## My Channels and Campaigns
Provide analysis for these channels:
- [CHANNEL_1]: $[SPEND_1] monthly spend, [CONVERSIONS_1] conversions/month
- [CHANNEL_2]: $[SPEND_2] monthly spend, [CONVERSIONS_2] conversions/month
- [CHANNEL_3]: $[SPEND_3] monthly spend, [CONVERSIONS_3] conversions/month
## What I Need
1. Calculate CAC for each channel (total spend ÷ conversions)
2. Calculate CAC payback period in months (CAC ÷ monthly gross profit per customer)
3. Identify which channels have payback periods under [YOUR_TARGET] months
4. Rank channels by efficiency and payback speed
5. Highlight which channels are dragging down overall unit economics
6. Recommend immediate reallocation opportunities (shift budget from slow-payback to fast-payback channels)
7. Show the revenue impact if I reallocate [X]% of budget from underperforming to high-efficiency channels
## Output Format
Provide:
- A summary table showing CAC, payback period, and efficiency ranking for each channel
- A narrative analysis of which channels are healthy vs. problematic
- Specific reallocation recommendations with projected impact
- Red flags: channels where payback exceeds [YOUR_ACCEPTABLE_PAYBACK] months
- Quick wins: low-lift optimizations that could improve payback by 10-20%
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Tips for Best Results
- 1.Include actual spend and conversion data, not estimates. Garbage in = garbage out. Pull numbers from your analytics platform or CRM to ensure accuracy.
- 2.Account for sales cycle lag: if your sales cycle is 30 days, CAC payback should factor in the delay between acquisition and first revenue recognition.
- 3.Use gross profit per customer, not revenue. If your COGS is 40%, a $100 customer generates $60 in gross profit—this is what actually pays back the CAC.
- 4.Run this analysis monthly and track payback period trends. A rising payback period signals channel fatigue, audience saturation, or competitive pressure—early warning for budget reallocation.
Example Output
## CAC Payback Analysis Summary
**Channel Performance Ranking:**
| Channel | Monthly Spend | Conversions | CAC | Monthly Gross Profit/Customer | Payback Period | Status |
|---------|---------------|-------------|-----|-------------------------------|-----------------|--------|
| Content + SEO | $8,000 | 24 | $333 | $450 | 0.74 months | ✅ Healthy |
| Paid Search | $12,000 | 32 | $375 | $450 | 0.83 months | ✅ Healthy |
| LinkedIn Ads | $6,000 | 12 | $500 | $450 | 1.11 months | ⚠️ Watch |
| Webinar + Email | $4,000 | 8 | $500 | $450 | 1.11 months | ⚠️ Watch |
| Display/Retargeting | $5,000 | 6 | $833 | $450 | 1.85 months | 🚨 Problem |
**Key Findings:**
Content and Paid Search are your efficiency engines—both payback in under a month. LinkedIn and Webinars are borderline; they're not broken but they're not driving velocity. Display/Retargeting is your biggest leak: $833 CAC with 1.85-month payback means capital is tied up longer and you're burning cash on low-intent traffic.
**Reallocation Recommendation:**
Shift $3,000/month from Display to Paid Search (proven 0.83-month payback). Projected impact: 8 additional conversions/month, reducing blended CAC from $475 to $438 and payback from 1.06 to 0.97 months. This frees up ~$2,500 in working capital monthly.
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