Decision Summary
Customer acquisition cost
$800.00
CAC is spend divided by acquired customers in the same period.
SaaS Growth Metrics
CAC Calculator
Calculate customer acquisition cost, payback period, and LTV:CAC efficiency using spend, conversion, ARPU, and churn assumptions.
Outcome Comparison
Primary result and the most important supporting metrics.
Customer acquisition cost
$800.00
Payback period
8 months
Gross profit / user / mo
$100.62
LTV
$2,515.50
Key Metrics
Payback period
8 months
Gross profit / user / mo
$100.62
LTV
$2,515.50
LTV:CAC
3.14
How to use it
- Enter sales and marketing spend, new customers acquired, monthly ARPU, gross margin, and monthly churn for the same measurement period. Include all true acquisition costs such as paid media, acquisition-focused sales labor, agencies, and tools, but exclude retention-only work if you want a clean CAC view.
- Read CAC, payback period, gross profit per user per month, LTV, and LTV:CAC ratio. As a rule of thumb, LTV:CAC of 3 or higher is healthy, under 1 means you lose money on acquisition, and payback above 18 months is cash-flow heavy for most growing SaaS businesses.
- Interpret the metrics together instead of cherry-picking one. A seemingly acceptable CAC can still be dangerous if payback is long, and a great LTV:CAC ratio above 5 can mean you are actually under-spending on a channel that deserves more budget.
- Use the result to set CAC caps per channel, adjust bid targets, and decide whether the next dollar should go to conversion improvement, lower spend, or retention. If CAC is fine but LTV:CAC is weak, churn is probably the more important fix than top-of-funnel volume.
- Re-run monthly and by channel or campaign cohort. Track CAC, payback, and LTV:CAC side by side over time because a falling CAC can still mask worsening retention or margin erosion.
AI Integrations
Contract, discovery endpoints, and developer notes for agent use.
Always available for agents
AI Integrations
Contract, discovery endpoints, and developer notes for agent use.
Tool contract JSON
https://aibizhub.io/contracts/cac-calculator.jsonStable input and output contract for this exact tool.
Human review
People can use the browser page to sense-check outputs and charts, but agents should still execute against the contract and discovery endpoints.
- /agent-tools.json - machine-readable tool index.
- /llms.txt - human-readable model discovery guide.
- /.well-known/webmcp.json - WebMCP capabilities manifest.
- /.well-known/ai-plugin.json - plugin-style discovery manifest.
{
"tool": "cac_calculator",
"sales_marketing_spend": 32000,
"new_customers": 40,
"arpu_monthly": 129,
"gross_margin_percent": 78,
"monthly_churn_percent": 4
} Expand developer notes
Agent playbook
- Resolve CAC Calculator from /agent-tools.json and open its contract before execution.
- Validate inputs against the contract schema instead of scraping labels from the page UI.
- Open the browser page only when a person wants to review charts, assumptions, or related tools.
Agent FAQ
Should ChatGPT, Claude, or another agent click through the UI?
No. Start with /agent-tools.json, then follow the tool's contract URL. The page UI is for human review, not parameter discovery.
When do tools show Quick and Advanced?
Every tool opens in Quick Start first. Advanced Controls keeps the same scenario, reveals more assumptions or diagnostics, and every tool keeps AI integrations inline below the instructions.
When should an agent still open the browser page?
Open it when a human wants to sense-check the output, review the chart, or keep exploring related tools after the calculation finishes.
Questions people usually ask
What is a good CAC to LTV ratio?
The 3:1 ratio is the standard benchmark: customer lifetime value should be at least 3× the cost to acquire them. At 3:1, you recover acquisition cost in roughly one-third of the customer relationship and profit the rest. Below 1:1 means you lose money on every customer. Above 5:1 often signals underinvestment in growth.
What is typically included in CAC calculation?
All sales and marketing costs to acquire a new customer: paid advertising spend, agency fees, sales team salaries and commissions (prorated to new acquisition activity), tools and software, events, content creation. Exclude account management and retention costs — those belong in LTV calculation.
How long should it take to recover CAC?
SaaS benchmarks: under 12 months is excellent, 12-18 months is typical for B2B, over 24 months signals cash flow risk. E-commerce: under 6 months is strong. The payback period determines how much capital you need to scale — a 6-month payback lets you reinvest quickly; 18 months requires sustained funding.
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Decision Workflows
Step-by-step guides that use this tool.