What is Payback Period and why does it matter?
Short Answer
Payback Period is the time (in months) for revenue from a customer to cover the CAC — calculated as CAC / Monthly Contribution Margin.
Full Explanation
If CAC is £8,000 and monthly contribution margin per customer is £667, payback period = £8,000 / £667 ≈ 12 months. This means the company needs 12 months of customer revenue to recover acquisition cost. Payback periods under 12 months are healthy for SaaS; under 6 months is exceptional. Longer payback periods (18+ months) tie up capital and are seen as risky — if churn accelerates or sales slow, the company may never recover the CAC. Payback period is closely related to CAC and LTV: a company can improve payback by (1) reducing CAC (more efficient sales and marketing), (2) increasing monthly revenue per customer (better pricing, upsells), or (3) improving gross margin (more profitable product). For early-stage companies, 12-18 month payback is accepted because the focus is growth; for growth-stage companies, 8-12 months is expected; for mature companies, 6-8 months indicates operational excellence. Investors use payback period as a signal of unit economics health — long payback periods with high churn is a red flag, while short payback and high NRR is a green light for increased investment.
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Further Reading
The Burn Multiple: Why Capital Efficiency Is the New Growth
The burn multiple has replaced growth rate as the metric investors scrutinise most. This guide explains the formula, stage-specific benchmarks, and why every dollar of burn should be creating an intangible asset that compounds in value.
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