Another popular parameter e-commerce companies quote is the gross merchandise value (GMV) to indicate the total sales value reflecting the volume of their business, Singhal said.

Currently, Flipkart, the country's highest valued e-commerce company, has said it expects its GMV to touch Rs 76,000 crore in a year.

Earlier, the company had said it expects to reach a GMV of USD 8 billion (over Rs 50,000 crore) by December. Snapdeal is also reported to be targeting GMV sales of USD 10 billion (about Rs 63,000 crore) by the end of calendar year.

While Amazon India does not share details of its sales, it's offering more than 25 million products for sale through its online marketplace.

It reportedly crossed USD 1 billion (Rs 6,300 crore) in sales in September last year while Flipkart reported a GMV of USD 3 billion for FY15. Snapdeal reportedly crossed the USD 3.5 billion mark by May.

"GMV is an important metric as far as size and scale of the company is concerned in e-commerce, but it is not the sole metric to gauge the health of business," Singhal said.

"In a marketplace model, the revenues for an e-retailer, which are a small margin of the sales, should also be taken into account," he added.

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