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The conversion ratio is a key performance indicator (KPI) of online marketing that measures the link between visits to a web portal and conversion. The conversion is not necessarily a sale, it can also be, for example, a subscription to the newsletter. For the Conversion Optimization (CRO), one of the KPIs The most important thing to review is the calculation of the number of users linked to the conversion.

Calculation of the Conversion Ratio

Today there are two common ways to calculate the conversion ratio.

1. General Formula

For the first formula, all the visits that a web portal receives and the impressions of that same user are taken into account. For this reason, this formula is the least exact option. However, it is a good way to get an approximation:

Conversion Rate = (Number of conversions x 100%) / (Number of visits)
  • Example

A Marketing expert sells eBooks on his web portal. In the first week after the launch ad campaign, the web portal gets 100,000 impressions and the eBook is downloaded 100 times. Thus:

Conversion Ratio = (100 x 100%) / 100000 = 0.1%

2. Improved Formula

To get a more precise value, the following model takes into account the "Unique visits". That is, each user who visits the web is counted as only 1 visit, even if he enters the web portal several times in the same day. To be sure exactly whether the number of unique visits obtained is correct, the web portal generally uses cookies that identify visitors. Formula:

IMPROVED Conversion Rate = (Number of conversions x 100) / (Number of unique visits)

For this calculation, a certain point in time is selected and only a conversion of the unique visits per day. The number of impressions has no relevance in this formula.


In general, experts in the field of Online Marketing have established that a 1% conversion ratio in e-commerce can be considered a standard. In practice, one in every 100 users makes a purchase through the online store. Successful online stores typically have a conversion ratio of the 10%. However, the conversion ratio it depends on many other factors, such as products, prices, and the month.

In general, stores that offer electronic products with prices below € 10 have a higher conversion ratio than a store that offers fireplaces with an average price of € 1,000, and a store that sells Halloween costumes will sell much more in October. than in any other month of the year.

Negative influencing factors

  • Few payment methods
  • Complicated login
  • Inappropriate SEA measures: users have different expectations of the ad
  • Unclear order processes
  • Buttons located in the wrong parts of the web portal
  • Captcha accreditation requests
  • Paid downloads

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