Introduction

Getting people to see an advertisement or visit a website is only the beginning of digital marketing.

The more important question is:

What did visitors actually do after arriving?

Did they:

• Submit a form?
• Register?
• Request a quotation?
• Add a product to the cart?
• Complete a purchase?
• Download a document?
• Book an appointment?

These actions are called conversions.

This article examines the metrics used to measure the movement from traffic to conversion and revenue.

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1. What Is a Conversion?

A conversion occurs when a user completes a desired action.

Depending on the business, conversions may include:

• Purchase
• Lead submission
• Registration
• App installation
• Demo request
• Newsletter subscription
• Booking
• Download
• Enquiry

Therefore, conversion is not synonymous with purchase.

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2. Conversion Rate

Formula

Conversion Rate (%) = (Conversions ÷ Total Visitors) × 100

Example

A website receives:

• Visitors = 20,000
• Conversions = 600

Therefore:

Conversion Rate = (600 ÷ 20,000) × 100

Conversion Rate = 3%

The website has a 3% conversion rate based on this definition.

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3. Cost Per Lead (CPL)

CPL is particularly important for businesses where the primary objective is lead generation.

Formula

CPL = Marketing Cost ÷ Number of Leads

Example

Marketing expenditure = ₹2,00,000

Leads generated = 500

CPL = ₹2,00,000 ÷ 500

CPL = ₹400

The organization spends an average of ₹400 to generate one lead.

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4. Cost Per Acquisition (CPA)

CPA measures the cost of generating a specified acquisition or conversion.

Formula

CPA = Campaign Cost ÷ Number of Acquisitions

Example

Campaign cost = ₹1,50,000

Customers acquired = 300

CPA = ₹1,50,000 ÷ 300

CPA = ₹500

The average acquisition cost is ₹500.

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5. Customer Acquisition Cost (CAC)

CAC focuses specifically on the cost of acquiring new customers.

Formula

CAC = Total Sales and Marketing Cost ÷ Number of New Customers

Example

Suppose a company spends:

• Advertising = ₹4,00,000
• Marketing software = ₹50,000
• Sales and marketing personnel allocation = ₹1,50,000

Total cost = ₹6,00,000

New customers = 600

CAC = ₹6,00,000 ÷ 600

CAC = ₹1,000

The average customer acquisition cost is ₹1,000.

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6. Lead-to-Customer Conversion Rate

A lead is not necessarily a customer.

Therefore, organizations should measure how many leads eventually become customers.

Formula

Lead-to-Customer Rate (%) = (Customers ÷ Leads) × 100

Example

Leads = 1,000

Customers = 100

Lead-to-Customer Rate = (100 ÷ 1,000) × 100

Lead-to-Customer Rate = 10%

This metric provides insight into lead quality and sales effectiveness.

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7. Average Order Value (AOV)

AOV measures the average amount spent per order.

Formula

AOV = Total Revenue ÷ Number of Orders

Example

Revenue = ₹10,00,000

Orders = 4,000

AOV = ₹10,00,000 ÷ 4,000

AOV = ₹250

The average order value is ₹250.

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8. Return on Advertising Spend (ROAS)

ROAS measures revenue generated relative to advertising expenditure.

Formula

ROAS = Attributed Revenue ÷ Advertising Cost

Example

Advertising expenditure = ₹2,00,000

Attributed revenue = ₹8,00,000

ROAS = ₹8,00,000 ÷ ₹2,00,000

ROAS = 4

This means the campaign generated ₹4 in attributed revenue for every ₹1 of advertising expenditure.

ROAS is a revenue-based measure and should not be confused with profit.

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9. Return on Investment (ROI)

ROI considers the return relative to the investment.

Formula

ROI (%) = [(Return − Investment) ÷ Investment] × 100

Example

Investment = ₹2,00,000

Return = ₹3,00,000

ROI = [(₹3,00,000 − ₹2,00,000) ÷ ₹2,00,000] × 100

ROI = 50%

ROI and ROAS answer different questions.

ROAS: How much attributed revenue did advertising generate?

ROI: What return did the investment generate relative to its cost?

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10. Ecommerce Funnel Metrics

An ecommerce journey can be represented as:

Product View → Add to Cart → Checkout → Purchase

Each stage can be measured.

Suppose:

Stage	Users
Product Views	50,000
Add to Cart	10,000
Checkout	7,000
Purchases	5,000

The organization can identify where users are dropping out.

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11. Cart Abandonment Rate

Formula

Cart Abandonment Rate (%) = [(Carts − Purchases) ÷ Carts] × 100

Example

Carts created = 10,000

Purchases = 7,000

Cart Abandonment Rate = [(10,000 − 7,000) ÷ 10,000] × 100

Cart Abandonment Rate = 30%

This means 30% of carts did not result in completed purchases under this calculation.

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12. Google Analytics 4 and Conversion Measurement

Google Analytics 4 uses events to measure user interactions.

Examples include:

• add_to_cart
• begin_checkout
• generate_lead
• sign_up
• purchase

Organizations can identify business-important events as key events in GA4.

The important principle is to design measurement around business objectives rather than simply collecting every available event.

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13. Example: Complete Campaign Analysis

Consider an ecommerce campaign:

• Advertising cost = ₹1,00,000
• Impressions = 500,000
• Clicks = 20,000
• Website visitors = 18,000
• Leads = 1,000
• Customers = 200
• Revenue = ₹4,00,000

CTR

CTR = (20,000 ÷ 500,000) × 100 = 4%

CPC

CPC = ₹1,00,000 ÷ 20,000 = ₹5

Visitor-to-customer conversion rate

Conversion Rate = (200 ÷ 18,000) × 100 = 1.11%

CAC

CAC = ₹1,00,000 ÷ 200 = ₹500

ROAS

ROAS = ₹4,00,000 ÷ ₹1,00,000 = 4

This is much more informative than simply saying:

“The campaign generated 500,000 impressions.”

The metrics show the entire journey from exposure → click → visitor → customer → revenue.

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14. Key Takeaways

Metric	Formula
Conversion Rate	Conversions ÷ Visitors × 100
CPL	Marketing Cost ÷ Leads
CPA	Campaign Cost ÷ Acquisitions
CAC	Sales & Marketing Cost ÷ New Customers
Lead-to-Customer Rate	Customers ÷ Leads × 100
AOV	Revenue ÷ Orders
ROAS	Attributed Revenue ÷ Advertising Cost
ROI	(Return − Investment) ÷ Investment × 100
Cart Abandonment	(Carts − Purchases) ÷ Carts × 100

The key lesson:

Traffic is an input. Conversion and revenue are outcomes.

But even revenue does not provide the complete picture.

A customer acquired today may purchase repeatedly over several years.

That takes us to the third article.

15. References

• Google Analytics Help — Events and key events.
• Google Ads Help — Advertising metrics.
• DataReportal — Digital 2026.
• Kotler, P., Keller, K. L. & Chernev, A. Marketing Management. Pearson.
• Chaffey, D. & Ellis-Chadwick, F. Digital Marketing: Strategy, Implementation and Practice. Pearson.