Velocity is a metric that predicts how much work an Agile software development team can successfully complete within a two-week sprint (or similar time-boxed period).
Velocity is a useful planning tool for estimating how fast work can be completed and how long it will take to complete a project. The metric is calculated by reviewing work the team successfully completed during previous sprints; for example, if the team completed 10 stories during a two-week sprint and each story was worth 3 story points, then the team's velocity is 30 story points per sprint.