PHPSimplex is an online tool to solve linear programming problems. It can be used for free.
This tool is thought for students mainly, because it does not only show the results but also operations step by step. Others of its advantages are that it does not need any specific language to enunciate the problem, offers a friendly interface, is closer to the user, easy and intuitive handling, it is not necessary to install any program to use it, and it will be available in several languages soon (actually only Spanish and English).
PHPSimplex is able to solve problems using the Simplex Method, the Two-Phase Simplex Method and the Graphical Method algorithm, and it does not have limits in the number of decision variables nor in the restrictions of the problems.
Help for PHPSimplex to learn quickly how to use the tool is also available.
Besides, in this page can be found theory of used methods, special cases to consider, examples solved step by step, comparison among the Simplex Method and the Graphical Method...