How to Calculate SaaS Unit Economics in 5 Minutes with Google Sheets

# How to Calculate SaaS Unit Economics in 5 Minutes with Google Sheets

As a SaaS founder, you probably know your monthly recurring revenue (MRR). But do you know your **unit economics**? If you can't answer these three questions, stop everything and read this:

1. What's your Customer Acquisition Cost (CAC)?
2. What's your Lifetime Value (LTV)?
3. Is your LTV:CAC ratio above 3:1?

Investors care about these numbers because they predict future profitability. Founders who don't track them often burn cash on unprofitable channels.

## The Problem With Manual Calculations

Most SaaS teams manually calculate CAC and LTV each month. They copy-paste from Stripe, Excel, and their ad platforms, hoping the numbers balance. This leads to:
- Version control chaos (six different spreadsheets with different CAC numbers)
- Missed churn trends (you don't see the 2% monthly churn creep until it's too late)
- Investor skepticism (when your spreadsheet has manual errors)

## The Fix: A Pre-Built Google Sheets Calculator

I built a **SaaS Unit Economics Calculator** — a Google Sheets workbook with 14 auto-calculations. It costs less than one hour of your bookkeeper's time. Here's what it does:

- **Auto-calculates CAC**: Input marketing spend + sales costs, divide by new customers = instant CAC
- **Estimates LTV**: Takes ARPU, gross margin, and churn rate. Formula: =ARPU/GrossMargin/(ChurnRate/100)
- **Tracks payback period**: How many months to recover CAC? Formula: =CAC/(ARPU-COGS)
- **Runs scenarios**: What if churn drops from 5% to 3%? What if ARPU goes to $60? Updated LTV in 2 seconds

The calculator includes sample data from a real SaaS company (500 subscribers, $50/mo ARPU, 5% monthly churn). You can replace the data with your own in less than 5 minutes.

## Sample Formula You Can Use Right Now

Even without the tool, here's a formula to calculate CAC:

`=IFERROR(SUM(Spend)/NewCustomers,0)`

Where `Spend` = total marketing + sales spend and `NewCustomers` = new subscribers acquired.

For LTV (simplified):

`=ARPU/GrossMargin/(ChurnRate/100)`

Example: ARPU = $50, Gross Margin = 70% (0.7), Monthly Churn = 5% (0.05)
LTV = $50 / 0.7 / 0.05 = $1,428.57

If your LTV:CAC ratio is below 3, your business model needs work.

## Get the Full Tool

I created a ready-to-use Google Sheets template called [**SaaS Unit Economics Calculator**] with 14 auto-calculations, scenario analysis, and a dashboard summary. It's available now — grab it at the link below.

[Link to Gumroad product]

*This template is for educational purposes and should be reviewed by your finance team before use in fundraising materials.*