CAC Payback Period
How long it takes for a customer to 'pay back' the cost of acquiring them. Payback = CAC / (Monthly ARPU × Gross Margin). Benchmark: under 12 months = healthy. Over 18 = risky.
In practice
Payback period is the business's 'breath.' If payback is 24 months, you need 24 months before the customer is profitable. Meanwhile, cash flow is negative. A store growing fast with a long payback period is raising capital to fund growth that isn't yet profitable.
Common misconception
'Payback period isn't relevant to eCommerce.' It's highly relevant. A store with CAC $33 and Contribution Margin $11/month = a 3-month payback. If repeat rate is low, the customer buys once and payback never happens.
How to fix it
Long payback period? (1) Lower CAC — organic channels, referrals, (2) Increase Contribution Margin — upsells, price increases, (3) Increase repeat rate — loyalty, subscriptions, win-back, (4) Check whether product-market fit exists — a long payback sometimes signals a product issue.
Example
SaaS with CAC $800, ARPU $80/month, Gross Margin 80% = a 12.5-month payback. Lowered CAC to $600 (referral program) + raised ARPU to $95 (feature upsell) = an 8-month payback. Cash flow improved significantly.
Priority
Calculate payback period before raising investment and before increasing budget. If above 12 months, focus on lowering CAC and raising repeat rate before scaling.
Related terms
Keep learning. Metrics that touch the same area:
- Cash FlowFinanceThe movement of cash in the business. 'Profitable on paper, broke in the bank' — a common problem in growing stores.
- ConversionAnalyticsA desired action a visitor takes — a purchase, sign-up, form submission. The basis for measuring marketing success.
- Conversion Rate (CR)AnalyticsThe percentage of visitors who completed a desired action. Average: 1-4% for purchases, depending on category.
- ATC – Add To CartAnalyticsThe action where a visitor adds an item to the cart. Average ATC rate: 8-10% of product page visits.
- Cart AbandonmentAnalyticsA customer added an item to the cart but didn't complete the purchase. Average: 70-75%. One of the biggest opportunities.
- Open RateAnalyticsThe percentage of recipients who opened the email. Average: 20-25% in eCommerce.
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