Digital Marketing Equations
From CPM to ROAS, learn the fundamental mathematics that separate bankrupt startups from viral ecommerce titans on the Facebook Ads and Google Ads networks.
The Advertising Funnel Physics
Digital advertising is entirely algorithmic. You buy attention (Impressions), convert that attention into action (Clicks), and manipulate those actions into sales (Conversions). Your success requires maintaining strict mathematical ratios down the entire funnel.
Standard Metrics
- CPM (Cost Per Mille): The dollar amount it costs to show your ad to 1,000 distinct people. (e.g., $10 CPM). This tests whether your audience targeting is cheap or fiercely competitive.
- CTR (Click-Through Rate): If 100 people see your ad and 2 click it, your CTR is `2.0%`. This mathematically tests if your ad creative (image/video) is compelling.
- CPC (Cost Per Click): Exactly how much money you pay Mark Zuckerberg every time a user taps your advertisement.
- CPA (Cost Per Acquisition): The cost to generate an actual paying customer (e.g., $20 CPA means you spent $20 on average for every 1 sale generated from clicks).
Return on Ad Spend (ROAS)
ROAS is the ultimate heartbeat metric of an ecommerce brand. If your ROAS is `100%`, it means you spent $1,000 and the ads generated exactly $1,000 in sales. Mathematically, because you have to pay to manufacture the product itself, a `100%` ROAS means you are losing massive amounts of money.
Most ecommerce brands require a minimum ROAS of `200%` just to hit break-even profitability. Anything over `300%` is incredibly lucrative and warrants immediately doubling your advertising budget.