Calculate unit economics (CAC, LTV, payback)
Customer acquisition cost, lifetime value, gross-margin payback and what to change to improve them.
This is a practical, copy-paste process for deciding whether to scale paid acquisition.. Use it when you want a clear structure, then add your own details and the linked evidence.
Published by Deepstory Research. Reviewed Sep 2026.
How to use this method
- 1. Copy or downloadCopy the prompt below, or download the method file and attach it to your chat.
- 2. Paste into any AIChatGPT, Claude, Gemini or Copilot. Replace each [PLACEHOLDER] with your details, or let the AI ask you.
- 3. Add evidenceAttach the evidence files listed on this page so the AI works from sourced numbers, not guesses.
The prompt
Paste it as-is. The AI will ask for anything still in [BRACKETS].
# Calculate unit economics (CAC, LTV, payback) Method by Deepstory Research: deepstoryresearch.com/method/unit-economics-cac-ltv You are a growth-finance analyst. Follow the method below step by step. Goal: Customer acquisition cost, lifetime value, gross-margin payback and what to change to improve them. ## My inputs - Marketing and sales spend: [MARKETING_AND_SALES_SPEND] (example: last 6 months by channel) - New customers: [NEW_CUSTOMERS] (example: by month and channel) - Revenue per customer and gross margin: [REVENUE_PER_CUSTOMER_AND_GROSS_MARGIN] (example: ₹1,200/month at 70%) - Churn or retention: [CHURN_OR_RETENTION] (example: monthly churn 4%) Before you start: if any input above is still in [BRACKETS] or missing, ask me for it in one short numbered list and wait. Do not guess. If I attached files (data, briefs, Deepstory evidence files), treat them as the primary source. ## Steps to follow 1. Compute blended and per-channel CAC. 2. Compute LTV using gross margin and churn (show formula). 3. Compute LTV:CAC and payback months. 4. Segment by channel or cohort if data allows. 5. Recommend where to scale, fix or cut. ## Deliver the output in this structure - Metric table with formulas - Channel comparison - Cohort view - Recommendations ## Quality rules - Use gross margin, not revenue, in LTV. - Warn if cohorts are too young to trust churn. - Label every number as FACT (with source and date), ESTIMATE (show the calculation) or ASSUMPTION. - If a Deepstory evidence file is attached, use its figures as the reference values and cite its source references; tag claims that are not from it as [UNVERIFIED]. - End with: the 3 assumptions that matter most, what would change the answer, and the single best next step.
What you need to give the AI
| Input | Placeholder | Example |
|---|---|---|
| Marketing and sales spend | [MARKETING_AND_SALES_SPEND] | last 6 months by channel |
| New customers | [NEW_CUSTOMERS] | by month and channel |
| Revenue per customer and gross margin | [REVENUE_PER_CUSTOMER_AND_GROSS_MARGIN] | ₹1,200/month at 70% |
| Churn or retention | [CHURN_OR_RETENTION] | monthly churn 4% |
Use it when
- Deciding whether to scale paid acquisition.
- Investors ask about unit economics.
What you get
- Metric table with formulas
- Channel comparison
- Cohort view
- Recommendations
The procedure, step by step
Read this before you run it, so you can check the AI actually followed the method.
Compute blended and per-channel CAC.
Compute LTV using gross margin and churn (show formula).
Compute LTV:CAC and payback months.
Segment by channel or cohort if data allows.
Recommend where to scale, fix or cut.
Quality checks built into the prompt
- • Use gross margin, not revenue, in LTV.
- • Warn if cohorts are too young to trust churn.
- • Every number labelled FACT, ESTIMATE or ASSUMPTION; claims outside attached evidence tagged [UNVERIFIED].
Evidence to use with this method
Methods tell the AI how to think. Evidence gives it sourced numbers to think with. Download a context file and attach it with the prompt.
Six-Economy Macro Baseline
A common-country, common-period baseline for real growth, inflation, modeled unemployment and trade exposure across the United States, China, India, Germany, the United Kingdom and Japan.
US Inflation & the Fed
The full 2026 inflation story on one page: the CPI path and category breakdown, the mid-year turn and the still-rising core PCE outlook, and the Fed’s rate response — fed funds, the 10-year Treasury, and the 30-year mortgage.
Private Credit: A $1.2 Trillion Disagreement
Estimates of global private credit AUM differ by more than a trillion dollars. This index shows the spread rather than picking a number.
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Deepstory methods are process guidance for AI tools. Review AI output before relying on it; legal, tax, medical and investment decisions need a qualified professional.