CAC Payback Calculator for SaaS growth teams

Calculate how many months it takes to recover customer acquisition cost, estimate LTV/CAC, and understand whether your acquisition model is healthy, risky, or too expensive to scale.

What this calculator shows

CAC payback is one of the clearest ways to judge whether paid acquisition, outbound, or GTM spend can scale without hurting cash flow.

PaybackMonths to recover CAC

LTV/CACEfficiency ratio

RiskGrowth health score

ChurnRetention impact

Inputs

Enter your acquisition and revenue assumptions. The calculator updates instantly.

CAC per customer ($)

Monthly revenue per customer ($)

Gross margin (%)

Monthly churn (%)

Extra onboarding/sales cost ($)

Monthly expansion revenue (%)

Results

Use these outputs to judge acquisition efficiency and SaaS growth risk.

CAC Payback

0 mo

Months to recover acquisition cost

LTV/CAC

Lifetime value divided by CAC

Gross profit / month

After gross margin

Estimated LTV

Based on churn and margin

Growth health score0/100

Enter your assumptions to see your CAC payback health.

What is CAC payback?

CAC payback measures how long it takes to recover the money spent to acquire a customer. In SaaS, it is usually calculated using gross profit, not just revenue, because delivery and service costs matter.

Under 6 months: very strong acquisition efficiency.
6–12 months: healthy for many SaaS companies.
12–18 months: workable, but needs strong retention and cash discipline.
18+ months: risky unless ACV, expansion, or retention is excellent.

CAC payback formula

CAC payback period = CAC / monthly gross profit per customer

Example: if CAC is $1,200, monthly revenue is $250, and gross margin is 80%, monthly gross profit is $200. CAC payback is 6 months.

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