Months to recoup CAC.

CAC payback is how long it takes to recoup customer acquisition cost from gross margin. Divide CAC by monthly gross margin per customer. The result - in months - tells a SaaS business when new customers start generating positive cash. Under 12 months is standard for growth-stage SaaS; under 6 months is excellent; over 24 months usually burns more cash than the business can sustain.

500 CAC on 100 MRR at 80% gross margin = 80/month. Payback = 500 ÷ 80 = 6.25 months. Strong. That means each new customer generates positive cash after 6 months. At 12,000 new customers per year, the CAC float (acquired customers not yet paid back) stays manageable.

CAC payback is often more actionable than LTV:CAC for cash planning. A 5:1 LTV:CAC looks healthy in isolation, but if payback is 36 months the business needs massive working capital to fund growth. CAC payback determines how quickly sales spend returns as cash. The shorter it is, the faster you can reinvest profits into more acquisition.

Run it with sensible defaults

Using cac of 500, avg mrr per customer of 100, gross margin of 80%, the calculation works out to 6.3 months. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — CAC, Avg MRR per Customer, and Gross Margin % — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

CAC payback = CAC ÷ (MRR × gross margin). Expressed in months. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Using this as a check-in

Re-run this every three months. A single reading tells you where you stand; four readings tell you whether things are improving. The trend matters more than any individual snapshot.

What this doesn't capture

The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.