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CAC Payback Period Calculator
Calculate how many months to recover your customer acquisition cost from gross profit, and check your LTV:CAC ratio health.
Try a preset
Result
- Payback at 24.8 months is unsustainable. Pause heavy acquisition spend and fix CAC or improve ARPU/margins first.
Unit Economics Snapshot
CAC vs estimated 24-month gross profit and LTV.
How to use it
- Enter CAC, monthly ARPU, gross margin percentage, and an optional target payback period such as 12 months. For SaaS, gross margins in the 60-80% range are common, and payback targets below 12 months are a frequent planning benchmark.
- Read monthly gross profit, payback months, estimated 24-month LTV, 24-month LTV:CAC ratio, payback health, LTV:CAC health, and the delta versus target. Payback of 6 months or less is excellent, 12 months is good, 12-18 months needs caution, and more than 18 months is a danger zone.
- Use the two health ratings together. If payback is acceptable but the 24-month LTV:CAC ratio is weak, retention is likely the limiting factor; if both are weak, acquisition efficiency or pricing is broken enough that scaling spend will magnify the problem.
- Act on the guidance by choosing the right lever: cut CAC, improve ARPU, raise gross margin, or pause heavy acquisition until onboarding and retention improve. If you are ahead of target by several months, that is an argument for increasing spend, not just celebrating efficiency.
- Re-run monthly by acquisition channel and cohort. Track payback against actual gross-margin changes over time because delivery-cost creep can quietly stretch the recovery period even if topline ARPU looks stable.
Questions people usually ask
What is CAC payback period?
CAC payback period is the number of months it takes to recover your customer acquisition cost from the gross profit that customer generates each month. Formula: CAC ÷ (Monthly ARPU × Gross Margin %).
What is a good CAC payback period?
For SaaS: ≤6 months is Excellent, ≤12 months is Good, 12–18 months needs attention, and >18 months is a red flag. Capital-intensive or enterprise businesses may tolerate longer periods.
What is a good LTV:CAC ratio?
3× or higher is the standard target for healthy SaaS unit economics. 5× or higher indicates room to scale acquisition spend aggressively. Below 1.5× means you're spending more to acquire customers than they're worth.
Why does this tool use a 24-month LTV horizon?
24 months is a commonly used benchmark for early-stage SaaS to avoid overestimating LTV from uncertain long-term retention. For more mature businesses with known cohort data, adjust the interpretation accordingly.
How is monthly gross profit calculated?
Monthly Gross Profit = Monthly ARPU × (Gross Margin % ÷ 100). This is the profit contribution per customer per month after cost of goods sold or service delivery costs.
Is this tool free and private to use?
Yes. AI Biz Hub tools run entirely in your browser with no signup required. Inputs stay local unless you share the URL.
Is this professional advice?
No. Outputs are planning estimates — not financial, legal, or accounting advice. Validate with your actual cohort data and an advisor.
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Decision Workflows
Step-by-step guides that use this tool.