CAC Payback Calculator
Enter your customer acquisition cost, contract value, and gross margin to get your payback period in months, a benchmark grade, and a prioritized fix list.
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Enter your CAC, annual contract value, and gross margin above. The payback period, benchmark grade, and fix list update live as you type — no button, no login.
Model CAC payback on your real data.
The unit-economics skills in the GTM Claude Skills bundle compute CAC payback, LTV:CAC, and margin by segment and channel — in Claude Code on your own numbers. 42 skills, $39 one-time.
Get the operator playbook ($39) →What is CAC payback?
CAC payback is the number of months it takes to recover the cost of acquiring a customer from the gross profit that customer generates. It's the clearest read on whether your growth is efficient: a short payback means each new customer funds the next; a long one means growth burns cash.
It matters more than raw CAC because it accounts for how much a customer is worth. A $30K CAC is fine if the customer pays back in 10 months, and alarming if it takes 30.
How to calculate CAC payback
Divide fully-loaded CAC by the monthly gross profit per customer: CAC ÷ (ACV ÷ 12 × gross margin). Fully-loaded CAC includes sales and marketing salaries, ad spend, and tooling — not just media cost. Gross margin adjusts revenue for the cost of serving the customer (hosting, support, data).
Example: $22,000 CAC, $24,000 ACV, 75% margin → monthly gross profit is $1,500, so payback is about 14.7 months.
What's a good CAC payback period?
The common benchmark is under 12 months for SMB and under 18–24 months for enterprise. Below 12 is excellent and signals room to spend more; 12–18 is healthy; 18–24 is slow and starts to strain runway; above 24 months the unit economics are underwater and scaling makes the cash problem worse.
Low gross margin is a hidden payback killer — every point of margin below the 75–85% SaaS norm stretches the period. So does a low ACV relative to CAC, which usually means the acquisition motion is too expensive for the segment.
Frequently asked questions
What is a good CAC payback period?
Under 12 months is excellent, 12–18 months is healthy for most B2B SaaS, 18–24 is slow, and above 24 months means growth burns cash. Enterprise motions can tolerate longer payback than SMB.
How is CAC payback calculated?
Divide fully-loaded customer acquisition cost by monthly gross profit per customer — that is annual contract value divided by 12, multiplied by gross margin. The result is the number of months to recover the CAC.
Why use gross margin in CAC payback?
Because you only recover CAC from profit, not revenue. A customer paying $2,000/month at a 75% margin returns $1,500/month toward CAC. Ignoring margin overstates how fast you actually break even.
What is the difference between CAC payback and LTV:CAC?
CAC payback measures how fast you recover acquisition cost; LTV:CAC measures how much total value a customer returns relative to that cost. Payback is the cash-flow view; LTV:CAC is the lifetime-return view. Healthy SaaS wants payback under ~18 months and LTV:CAC above 3.
How do I improve CAC payback?
Three levers: lower CAC (shift spend to efficient channels, tighten targeting), raise ACV (packaging, expansion at point of sale), and raise gross margin (reduce COGS). Segment-level analysis usually reveals one motion dragging the blended number.