Compute your CAC, payback, and LTV:CAC

CAC Calculator

Enter your sales & marketing spend and net-new customers for any period. The calculator also computes payback period and LTV:CAC ratio if you provide ARPU and gross margin. Your inputs encode into the URL - copy and paste to share.

Results

CAC

$10.0k

S&M $1.00M ÷ 100 net-new

Payback period

26.7 mo

CAC ÷ (gross profit / month). Gross profit/mo = $375

Customer lifetime

50.0 mo

1 ÷ monthly churn rate (2%)

LTV

$18.8k

Gross profit/mo × customer lifetime

LTV : CAC ratio

1.88:1

Below 3:1 but unit-economic positive

What these numbers mean

CACS&M ÷ net-new customers. Same formula as every public-company page on this site. See the formula page for the four CAC variants and when each applies.

Payback Period (months)CAC ÷ (Monthly ARPU × Gross Margin). How many months of gross profit per customer it takes to recoup their acquisition cost. The SaaS Capital 2024-2025 median was around 32-36 months; sub-12 is exceptional.

LTV (Lifetime Value)Monthly ARPU × Gross Margin × Average Lifetime (months). Average lifetime is 1 ÷ monthly churn rate - this calculator uses the canonical churn assumption you provide. LTV is sensitive to churn assumptions; small changes compound.

LTV:CAC RatioThe 3:1 rule of thumb from David Skok. Above 3 is canonically healthy; below 1 means losing money on every customer. The rule is a starting point - different business models reasonably tolerate different ratios.