Enter the change in radial position/distance and the change in time into the calculator to determine the radial velocity.

Radial Velocity Formula

The following equation is used to calculate the Radial Velocity.

Vr = Δr / Δt
  • Where Vr is the radial velocity (rad/s)
  • Δr is the change in radial position (radians)
  • Δt is the change in time (s)

To calculate radial velocity, divide the change in radial position by the change in time.

What is a Radial Velocity?


A radial velocity, also commonly referred to as angular velocity, is a measure of the change in radial position per unit of time.

How to Calculate Radial Velocity?

Example Problem:

The following example outlines the steps and information needed to calculate Radial Velocity.

First, determine the change in radial position. In this example, the change in radial position is found to be 50 radians.

Next, determine the change in time. In this case, the change in time is measured to be 5 seconds.

Finally, calculate the Radial Velocity using the formula above:

Vr = Δr / Δt

Vr = 50 / 5

Vr = 10 radians /s