The bounce rate is a measure of the percentage of visits to a web page that end with the visiting web user leaving the website. To calculate the bounce rate of any web page, simply dividing the number of visits that end in the user leaving by the total number of entrances (not visits) to that page.
According to John Mueller from Google, the bounce rate is not taken into account when ranking sites, so it shouldn’t affect SEO.
Still, low bounce rates are an indicator of web pages that are successfully engaging visitors. Low bounce rates are also a sign that a web page is attracting relevant traffic.