The Basic ROI Formula
ROI = [(Net Profit - Marketing Investment) / Marketing Investment] x 100
For example, if you spent R5,000 on a Google Ads campaign that generated R20,000 in revenue with a 50% margin (R10,000 profit):
ROI = [(R10,000 - R5,000) / R5,000] x 100 = 100%
Step 1: Define Your KPIs
For E-commerce:
- Conversion Rate: Percentage of visitors who purchase.
- Average Order Value (AOV): Average amount spent per order.
- Customer Lifetime Value (CLV): Total profit from a customer over time.
- Cost Per Acquisition (CPA): Cost to acquire one new customer.
For B2B / Lead Generation:
- Cost Per Lead (CPL): Cost to generate one new lead.
- Lead-to-Customer Conversion Rate: Percentage of leads becoming customers.
- Marketing Qualified Leads (MQLs): Leads likely to become customers based on behaviour.
- Sales Qualified Leads (SQLs): Leads ready for direct sales follow-up.
Step 2: Set Up Tracking
- Google Analytics 4 (GA4): Foundation for tracking website traffic, behaviour, and conversions.
- Google Tag Manager (GTM): Manage and deploy tracking tags without modifying code.
- CRM Software: Track leads from first interaction through to final sale for complete ROI picture.
Step 3: Understand Attribution Modeling
A customer's journey is rarely linear. Attribution modeling determines which channel gets credit.
- Last-Click: 100% credit to the last touchpoint. Simple but misleading.
- First-Click: All credit to the first touchpoint. Good for understanding awareness channels.
- Linear: Distributes credit evenly across all touchpoints.
- Data-Driven (Gold Standard): Uses machine learning to determine credit distribution.
Step 4: Bring It All Together
1. Track your investment per channel
2. Track returns using analytics and CRM
3. Calculate ROI per channel
4. Analyse and optimise — double down on what works
Conclusion
Measuring ROI transforms marketing from an expense into an investment. Start by defining goals, setting up robust tracking, and paying close attention to your data for continuous improvement.