How do I calculate CAC payback period?

Divide fully loaded sales and marketing cost for a period by the net new customers won in that period to get CAC. Multiply ACV by gross margin percentage and divide by 12 to get monthly gross profit per customer. Then divide CAC by that monthly gross profit. The result is your payback in months.

What is a good CAC payback period for B2B SaaS?

For companies between $1M and $10M ARR, under 12 months is healthy, under 6 months is excellent, 12 to 18 months is typical but worth watching, and above 18 months signals a structural problem in CAC, ACV, or gross margin.

SaaS CAC Payback Period Calculator (Free)

How the calculation works

CAC = sales & marketing spend ÷ new customers won in the same period. Monthly gross profit per customer = (ACV × gross margin %) ÷ 12. Payback months = CAC ÷ monthly gross profit. The result tells you how many months of gross profit it takes to repay what you spent to win a customer.

Two numbers quietly distort most teams' payback: undercounted CAC (forgetting loaded salaries, tools, and agency fees) and overstated gross margin (ignoring implementation services and third-party pass-throughs). Use a clean, fully loaded quarter and the number gets honest.

If your payback is too long

Cutting spend rarely fixes payback — it compresses the numerator without touching the broken driver. The fastest, most durable levers are raising ACV (higher tiers, annual prepay) and protecting gross margin (services, pass-throughs, discount discipline), followed by structurally reducing CAC in the funnel.

How the calculation works

If your payback is too long

Go deeper

Know the number. Now move it.