Constant Acceleration Average Velocity Calculator

I want to calculate
Initial Velocity(v0) = m/s
Velocity(v) = m/s
Average Velocity(va) = m/s
 

The average velocity to say the constant velocity

Constant Acceleration Average Velocity formula:

Average Velocity: va = ½ (v0 + v)

where v is final Velocity, v0 is Initial Velocity.

The formula could transform to Initial Velocity: v0 = 2xva - v, to Velocity: v = 2xva - v0