The Math of Marketing: Predicting ROI

Most businesses treat Google Ads like a slot machine: put money in, pull the lever, pray for leads. Smart marketers treat it like a vending machine: Put $1 in, get $5 out.

But how do you know if the math works?

The Golden Formula

You don't need complex software. You just need 3 numbers:

1. Average Order Value (AOV): How much is a customer worth? (e.g., $1,000).
2. Conversion Rate (CR): What % of clicks become leads? (Average is 3-5%).
3. Close Rate: What % of leads become sales? (e.g., 20%).

Calculating Max CPC (Cost Per Click)

Let's work backward. If you want a 400% ROI (4x ROAS), you can only spend 25% of your revenue on ads. So, you can spend $250 to acquire a customer worth $1,000.

If your close rate is 20%, you need 5 leads to get 1 sale. $250 / 5 leads = $50 CPA (Cost Per Lead).

If your website conversion rate is 5%, you need 20 clicks to get 1 lead. $50 / 20 clicks = $2.50 Max CPC.

The Result: If "Dentist in Austin" keywords cost $15 per click, and your math says you can only afford $2.50, do not run ads. You will lose money.

Use Our Tool

We built an interactive tool to do this math for you. Try the ROI Calculator Here

Improving the Numbers

If the math doesn't work, you have two options:

1. Increase Conversion Rate: Fix your landing page.
2. Increase LTV (Lifetime Value): Sell more to existing clients.

Google Ads amplifies your business model. It cannot fix a broken one.