ROAS calculator using Google Ads API

Return on Ad Spend is a KPI that tells you whether your campaigns are delivering real business value. The problem is that because your data typically is stuck in various ad platforms–calculating ROAS is a time-consuming, manual task. Most marketing teams look at ROAS quarterly or monthly.

However, the faster you can swap out an ineffective campaign or double down on a high-performing campaign, the faster you can improve the effectiveness of a given marketing channel. This can be instrumental to building out new ad channels, or even trying more types of experiments to give your product an edge in the market.

Step by Step:

**Before you start you need:

From your Google Ads Account: Login Customer ID + Developer Token
From your Google Cloud Console Project: OAuth Client ID + Client Secret
Visiting https://developers.google.com/oauthplayground/ to generate a temporary access Token.

1. Fetching data from Google Adwords API: using the POST Request node. Below the configuration:

- Connection URL with your Customer ID inside:

https://googleads.googleapis.com/v10/customers/${CUSTOMER_ID}/googleAds:searchStream

- Body request: Google Ads Query to obtain your desire data.

- Request Headers: Developer token, Login-customer-id (aka Google ads Manager Account ID, and an Authorization token.

2. Obtaining Company Revenues by GAds campaigns using an Excel Reader node

3. Joining and Calculating ROAS: Joiner node + Math formula node.

Math node formula to calculate ROAS: round(($revenues_last_30days$/$cost$)*100,0)

4. Output: you can choose the output that you prefer: Excel file, Tableau source, DB or Gsheets between many others.

External resources

• KNIME blog article walking you through this worklow
• How to obtain a developer token
• OAuthPlayground
• Google Ads API overall documentation
• Google Ads API query builder