Formula
How to Calculate CAC Payback Period
The number of months required to recover the cost of acquiring a customer from the gross profit that customer generates — a core measure of go-to-market efficiency.
CAC Payback Period (months)
CAC Payback = CAC / (ARPA x Gross Margin %)
Where
- CAC
- = Customer Acquisition Cost
- ARPA
- = Average Revenue Per Account (monthly)
- Gross Margin %
- = Gross margin as a decimal (e.g. 0.80)
What Is CAC Payback Period?
CAC Payback Period = CAC / (MRR per Customer × Gross Margin %) Benchmarks: SMB SaaS targets 12-18 months; mid-market 18-24 months; enterprise 24-36+ months given higher ACV and retention. Companies with payback periods under 12 months have exceptionally efficient go-to-market motions. Short payback periods mean cash from new customers funds acquiring the next wave — a highly capital-efficient, self-funding growth model.
Worked Example
A company spending $2,400 to acquire a customer paying $200/month at 75% gross margin: payback = $2,400 / ($200 × 0.75) = 16 months. If that customer churns at month 14, the company never recovered its CAC.
Why CAC Payback Period Matters
VCs increasingly use CAC payback as the primary efficiency metric at Series A and B. Companies with sub-18-month payback can grow faster with less capital. Those with 36+ month payback need to show exceptional retention and LTV to justify the model.
Related Terms
Frequently Asked Questions
How do you calculate CAC Payback Period?
CAC Payback Period is calculated using the formula: CAC Payback = CAC / (ARPA x Gross Margin %). The number of months required to recover the cost of acquiring a customer from the gross profit that customer generates — a core measure of go-to-market efficiency.
What is a good CAC Payback Period?
What constitutes a "good" CAC Payback Period depends on context — the fund's stage, vintage year, and strategy. Check our benchmarks and calculators for specific ranges.