A bounce rate is a measure that helps you determine if the right people are finding your website and if your visitors are finding any value in what you are offering.
For example: If visitor A lands on your webpage and immediately returns to where they came from that is a 100% bounce rate. If visitor B lands on your page and finds one button to push or link to select then the bounce rate is zero. If you average both visitors A & B the bounce rate is 50%.
The goal is to earn a very low bounce rate. The best bounce rate I’ve ever achieved is a 2% bounce rate for prosperous artists academy a few years ago. I have a current client that has about a 6% bounce rate. Rates that low are rare. A good bounce rate for a website is 25-35%. Blogs tend to a have higher bounce rate because people find what they need and leave. A 75% bounce rate for a blog is not that uncommon.
Here is a helpful post: 20 things to consider to reduce your bounce rate.