AI SaaS CAC & Payback Calculator

Calculate CAC payback after monthly LLM inference and RAG costs reduce customer contribution margin.

Inputs

Marketing spend ($/mo)

Sales spend ($/mo)

New customers / month

ARPU ($/mo)

Base gross margin before AI COGS: 0.85

LLM cost / customer / month ($)

RAG + vector cost / customer / month ($)

Blended CAC

$400.00

Decision Summary

Best move

Scale spend

Expected savings

Already optimal

Watch out

Validate quality, latency, and reliability on your own workload before changing production traffic.

Next step

Review the comparison table and pricing sources before making the decision.

Scale spend

CAC payback of 6.6 months is within the 12-month target — acquisition is efficient.

CAC payback

6.6 mo

Marketing-only CAC

$266.67

Gross margin / cust

$60.50/month

AI COGS / customer

$7.50/month

Health

healthy

Cost breakdown

Item	Monthly	Yearly
Marketing spend	$40,000.00	$480,000.00
Sales spend	$20,000.00	$240,000.00
LLM inference COGS / customer	$6.00	$72.00
RAG / vector COGS / customer	$1.50	$18.00

Comparison

Option	Monthly	Yearly
Blended CAC6.6 mo paybackcurrent	$400.00	$400.00
Marketing-only CACcheapest	$266.67	$266.67

Pricing sources

Last verified 2026-06-30 · ChartMogul SaaS Benchmarks chartmogul.com/reports/saas-benchmarks/ · Bessemer Cloud Index www.bvp.com/atlas/state-of-the-cloud · David Skok LTV:CAC standard www.forentrepreneurs.com/saas-metrics/

Industry Benchmark

Payback vs. 12-month planning referenceIndustry avg: 12 months

You are at the 72th percentile

Pricing sources

Trends & comparison

Trend

Comparison (monthly vs. yearly)

How to use this calculator

Enter acquisition spend, customers, ARPU, base margin, and measured per-customer LLM and RAG costs. The result uses contribution after AI COGS for payback.

Why payback period matters

Shorter payback means faster cash recovery and lower funding needs. The benchmark bar compares yours to the target window.

Sources

CAC and payback period benchmarks are sourced from public SaaS industry reports including OpenView's SaaS Benchmarks and ChartMogul data, versioned in the platform configuration.

Frequently asked questions

How is CAC calculated?▾

Blended CAC = (marketing + sales spend) ÷ new customers acquired in the period.

What is AI SaaS CAC payback?▾

Payback months = CAC ÷ (ARPU × base gross margin minus monthly LLM and RAG COGS). The 12-month value shown is a planning reference, not a universal benchmark.

How do I improve CAC?▾

Raise conversion, shift to cheaper channels, or increase ARPU/margin. The calculator shows the CAC that hits the target payback.

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