CAC Payback Period
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LTV : CAC
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LTV (gross)
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Real CAC (blended)
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Month-by-month ROI per customer
| Month | Cumulative revenue | vs CAC | ROI |
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€ Investor benchmarks (2026)
≤ 12 months
Great
12–18 months
Acceptable
> 24 months
Red flag
How many months until a new customer pays back what it cost to acquire them?
| Month | Cumulative revenue | vs CAC | ROI |
|---|
This calculator turns acquisition spend into a payback timeline. It combines your customer acquisition cost — including sales team cost spread across new customers — with monthly revenue per customer and gross margin to find how many months of contribution margin are needed to recover what you paid to win the customer. It also estimates expected customer lifetime from your churn rate, giving an LTV:CAC ratio and customer-level ROI. For API and cloud businesses this matters because gross margin is not fixed: inference, egress, and compute costs per customer directly reduce the margin available to repay CAC, so a rising cost-to-serve lengthens payback even when revenue and CAC stay flat.
For B2B SaaS, under 12 months is generally considered healthy and under 6 months is strong; 18 months or more usually signals an efficiency problem. Benchmarks vary by contract size and sales motion — self-serve products typically pay back faster than enterprise sales.
CAC is repaid from contribution margin, not top-line revenue. If a customer pays $500/month but costs $150/month in API, inference, and infrastructure spend, only the $350 margin goes toward recovering acquisition cost, so ignoring margin understates payback by the full cost-to-serve.
Expected customer lifetime is approximated as 1 divided by the monthly churn rate, so 2% monthly churn implies about 50 months. Higher churn shortens lifetime and lowers lifetime value, which reduces the LTV:CAC ratio even if the payback period itself is unchanged.