What is the Midpoint Formula?

Hand touching two points on digital ruler
Hand touching two points on digital ruler. Paper Boat Creative / Getty Images

The midpoint formula is applied when one is required to find the exact center point between two defined points. So for a line segment, use this formula to calculate the point that bisects a line segment defined by the two points. 

The Midpoint Formula: Definition of Midpoint

The midpoint is a give-away with its name. What is the exact halfway point between two points? Hence the name midpoint.

A visual for the Midpoint Formula

The lines through P1 and P2, parallel to the y-axis intersect the x-axis at A1(x1,0) and A2(x2,0). The The midpoint through M parallel to the y-axis bisects the segment A1A2 at point M.

M1 is halfway form A1 to A2, the x-coordinate of M1 is:

x1 + 1/2 ( x2 - x1) = x1 + 1/2 x2 - 1/2 x1

= 1/2 x1 + 1/2 x2

=( x1 + x2) ÷ 2