A function of the form $y = ax^{2}+bx+c$ is called quadratic function, where a, b and c are constants. The  graphical representation of quadratic function is called a parabola. Every parabola is symmetric about a vertical line called its axis of symmetry. The vertex of a parabola is a point on which the axis of symmetry passes through.

 The figure shows  the parabola corresponding to a function.  
Parabola

The coordinates of the vertex are (h,k) = $($$\frac{-b}{2a}$$,f($$\frac{-b}{2a}$$))$. The equation of the axis of symmetry is $x = $$\frac{-b}{2a}$$.
Vertex Calculator is a mathematical tool which will help us to find the vertex of any parabolic function of the form $y = ax^{2}+bx+c$.  

The following are the steps to find the vertex 
Step 1: Find the x coordinate of the vertex by solving $\frac{-b}{2a}$.

Step 2: Because the axis of symmetry is parallel to y-axis and passes through the vertex. The y coordinate of the vertex can be determined by substituting this values of x into $y = ax^{2}+bx+c$ and solve for y.

Step 3: Hence we can write the vertex (h,k) = $($$\frac{-b}{2a}$$,f($$\frac{-b}{2a}$$))$