The very definition of the word calculus is derived from a mineral build-up and means "hard". The Mathematical term of calculus describes a field that is a theoretical offshoot of algebra that attempts to define the way in which events will change over time. Calculus is used to determine the slope of a variable, or chosen identity, and how its rate of change may change over time. The calculations usually produce a curve or graphical presentation rather than a discreet sum and the information is read from points in the curve, which reflect the rates of change. There are relatively simply calculus theorems that will allow the calculation of how often the phone will ring over the next month, or a how a population of deer will grow in the upcoming years.
However, calculus is meant to be a theoretical tool that describes hypothetical situations thereby imparting clarity upon the unknown. Many would be happy to let the unknown remain that way, but if calculus is on your agenda, you may need calculus help in the near future, and you can figure on this without a formula.
The field of modern calculus was largely worked out by Leibnitz, a German Mathematician who lived in the 1600's. He was a genius who conquered Latin and began study of the Greek language and many other fields of learning by the time he was twelve. Shortly thereafter, he began the study of Law, but more relevant was his travel to Paris later in his life. It is here that he met the famous mathematician Huygens who routed the genius of Leibnitz toward the study of mathematics in general and to geometry in particular. It was he that developed the theories of Integrated and Differential Calculus, which remained largely unused until the complexity of the twentieth century brought these disciplines to the forefront. Differential calculus was then used in determining the rates of velocity, mass and was useful in the trajectory of rockets. Fourier calculations are based upon integral calculus. Integral calculus was used to determine the rate at which the door on the space shuttle can close.
Although calculus was developed by Leibnitz and furthered by other great mathematicians who followed him, it is thought that some elements of the science existed as early as the time of the ancient Greeks. It is thought that at this time, Exodius developed the Method of Exhaustion that contains rudiments of modern calculus. When you find that the Methods of Exhaustion are directly applying to yourself, it is time to seek help with Calculus.
The Mathematics study lab at your school, if there is one, will be happy to set you up with a tutor. If this is not possible, ask your teacher if he or she can recommend a tutor or approach someone who seems to get "A's" on their work and ask for help. Remember that calculus is a discipline that builds upon itself. Therefore, each stage must be clear in your mind or the subsequent steps will be out of reach. Try to get calculus help early in the game and stay with each topic as it is introduced.