Before moving on to what a limit calculator is used for, let us understand what the limit of a function means. There are plenty of fundamental concepts in mathematics and the limit of a function is one of the most important ones. The study of limits involves taking concepts of analysis and calculus in mind and it mostly revolves around the behavior of a particular function which is projected on a graph. First of all, you need to understand how a function is depicted on a graph. As we know, there are primarily three axes in a graph namely x-axis, y-axis and z-axis. Hence, each point on a graph represents an equation which will have variables in it. Each of the variables will be in each of the planes of the graph.