3D Midpoint Formula
The formula for the midpoint in 3D is an extension of the 2D formula. You simply average the z-coordinates as well.
M = ( (x₁ + x₂)/2 , (y₁ + y₂)/2 , (z₁ + z₂)/2 )
Midpoint in 3D Space Calculator
Find the midpoint of a line segment in three-dimensional space given two points (x₁, y₁, z₁) and (x₂, y₂, z₂).