Midpoint Calculator

Easily find the midpoint between two coordinates, or calculate a missing endpoint when given the midpoint and the other point. This tool is great for geometry problems, graphing, and coordinate-based math.

How to Use the Calculator

• Choose between Midpoint or Endpoint mode.

• Enter the values for the known coordinates.

• Click Calculate to see the result displayed below the form.

Formulas:

Midpoint Formula

To find the midpoint $M$ between two points $A(x_1, y_1)$ and $B(x_2, y_2)$:

$$M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)$$

Endpoint Formula

If you know the midpoint $M(x_m, y_m)$ and one endpoint $A(x_1, y_1)$, the other endpoint $B(x_2, y_2)$ is:

$$x_2=2x_m-x_1;y_2=2y_m-y_1$$

Example:

Midpoint Example
Find the midpoint between $(2, 4)$ and $(6, 8)$:

$$M = \left( \frac{2 + 6}{2}, \frac{4 + 8}{2} \right) = (4, 6)$$

Endpoint Example
Find the missing endpoint if midpoint is $(5, 7)$ and one endpoint is $(3, 5)$:

$$x_2 = 2 \cdot 5 – 3 = 7 \quad ; \quad y_2 = 2 \cdot 7 – 5 = 9$$

So the missing endpoint is $(7, 9)$.