How to Calculate SaaS Unit Economics in Google Sheets (Free Template Inside)

Why Unit Economics Matters More Than MRR

Most SaaS founders obsess over MRR growth while ignoring unit economics — the per-customer math that determines if your business is actually sustainable.

I recently built a Google Sheets template to track LTV:CAC, churn, and payback periods. Here's the formula walkthrough.

The Key Metrics

1. LTV:CAC Ratio — you want >3:1
   LTV = ARPU / Monthly Churn × Gross Margin %
   CAC = Cost to acquire one customer

2. CAC Payback — <12 months is healthy
   Payback months = CAC / (ARPU × Gross Margin %)

3. Monthly Churn — target <5% for B2B, <8% for B2C

The Problem With DCF Models

Static valuation models break for subscription businesses. A cohort tracker (month-by-month retention) reveals the real story.

Free Template

I've pre-filled a Google Sheets calculator with sample data for a $29/mo SaaS product at 5% churn. Grab it here: SaaS Unit Economics Calculator

Paste your data, see your unit economics live in 5 minutes.