Glossary
Conversion Rate
The share of visitors who take the action you wanted, calculated as conversions divided by total visitors.
Conversion rate is the percentage of visitors who do the thing you wanted them to do, whether that is buying, opting in, or clicking through. You calculate it by dividing conversions by total visitors.
Conversions / Visitors = Conversion rate
6 sales / 300 visitors = 2% conversion rate
The action counts as a conversion only if you defined it that way. On a sales page a conversion is usually a purchase. On a squeeze page it is usually an email signup. The same traffic can have a high signup rate and a low purchase rate, so always say which conversion you mean.
Conversion rate matters because it decides how far your traffic goes. If you double the rate, you get twice the results from the exact same visitors, with no extra ad spend. That is why experienced marketers work on the page before they buy more traffic.
Two cautions. First, the number is only trustworthy after a real sample; three sales out of ten visitors is noise, not a 30% rate. Second, a high conversion rate on the wrong visitors still loses money if those buyers do not stick around.
To see how to read and improve the number, read conversion rate explained.