All termsMETRICS & KPIS

Payback Period

Also known as: CAC Payback · CAC Payback Period

DEFINITION

The number of months required to recover the cost of acquiring a customer through that customer's gross profit.

In depth

Payback period is the sharper cousin of LTV/CAC because it measures cash flow, not just profitability. Two businesses with identical LTV/CAC can have wildly different payback — one might recover CAC in 6 months, the other in 24. The shorter one grows faster with less capital.

It's especially important for bootstrapped founders because long payback burns cash even if unit economics look fine on paper.

Formula & example

Payback = CAC ÷ (ARPU × Gross Margin)

EXAMPLECAC $800, ARPU $100, Gross Margin 80% → Payback = $800 ÷ ($100 × 0.8) = 10 months.

Rules of thumb

Under 12 months = strong, especially for bootstrapped.
12–18 months = acceptable if LTV is high.
Over 24 months = only sustainable with serious funding.

Put it into practice

tool

LTV/CAC Calculator

Related terms

CAC

The fully-loaded cost of acquiring one paying customer, including sales + marketing + tooling.

LTV

The total revenue a single customer generates across their entire relationship with your SaaS.

Gross Margin

The percentage of revenue left after deducting the direct cost of delivering the service (hosting, support, payment fees).

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Last reviewed 14 April 2026 by Abhi Verma.