Factor by Grouping Calculator is an online tool to find the factors of any equation which is in the form $Ax^{2} + Bx + C$ = $0$. For finding the factors of a given polynomial, one has to type the coefficients of the quadratic equation in the respective fields given in the calculator. The results shown are the factors of the quadratic equation entered.
Factoring by grouping calculator works on the principle by splitting the middle term in the quadratic equation into two terms, so that their product is equal to the constant term and their sum is equal to the second term in the polynomial.

That is $x^{2} + 4x + 3$ = $x^{2} + 3x + x + 3$

where, $3x + x$ = $4x$ (the middle term)

              $3 \times 1 = 3$ (the constant term)

Group the equation by taking out the common terms.
 
That is, $x^{2} + 3x + x + 3$ can be written as $x(x + 3) +1(x + 3)$

                                                                   = $(x + 3) (x + 1)$ 

Here $x = -3$ and $x = -1$ are the factors of given equation.