Your team's velocity is the amount of work the team has shown it can complete in a sprint. You can use this information to help estimate how much work can be completed in future sprints.
You can see your team's current average velocity in the planning folder summary page. The average velocity value remains current with the value in burndown.
Velocity only makes sense as a relative measure. There is no specific velocity that is good or bad or standard, because no two teams take on work of exactly the same scale or complexity. However, if your team's velocity is increasing from sprint to sprint, you can surmise that you are on the right track.
To calculate the velocity of a planning folder, you must find out the difference in the remaining effort between the first and last record in a sprint and divide it by the number of days in between these records. In other words, it is the average decrement in effort between the first and last recorded remaining effort.