Enter the proper distance and the peculiar velocity into the calculator to determine the recessional velocity.

## Recessional Velocity Formula

The following equation is used to calculate the Recessional Velocity.

Vr = H * D + Vpec
• Where Vr is the recessional velocity (MPH)
• H is the hubble constant (342,000 MPH/light year)
• D is the proper distance (light years)
• Vpec is the peculiar velocity (MPH)

To calculate the recessional velocity, multiply the Hubble constant by the proper distance, then add the peculiar velocity.

## What is a Recessional Velocity?

Definition:

A recessional velocity is a speed at which astronomical objects recede from an observer due to the expansion of the universe.

## How to Calculate Recessional Velocity?

Example Problem:

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

First, determine the proper distance. In this example, the proper distance is found to be 400 light years.

Next, determine the peculiar velocity. For this problem, the peculiar velocity is found to be 30,000 MPH.

Finally, calculate the Recessional Velocity using the formula above:

Vr = H * D + Vpec

Vr = 342,000 * 400 + 30,000

Vr = 136,830,000 MPH