There are many branches of mathematics that are existing nowadays and one of these includes calculus, which is also categorized into two; the differential calculus and integral calculus. Differential calculus deals with computing or finding the derivatives of the functions to be able to know the rate of change and the behaviour the function. On the other hand, integral calculus deals with integrals to be able to determine the areas, volumes, and lengths. As we use and study calculus, it made me wonder who discover or invented it. And as I did my research, I found out that there were two people who were known when we are talking about the discovery and history of calculus namely Sir Isaac Newton and Gottfried Wilhelm von Leibniz. These two are great mathematician who contributed a lot in the field of calculus but if you are going to ask who discovered calculus, the answer is still unclear because calculus is discovered by many people over centuries. The idea and some concept of calculus is already present during Greek times. During ancient Greek times, Eudoxus a Greek mathematician used the method of exhaustion (one thinks of the areas measured expanding so that they account for more and more of the required area), a precursor to limits in order to calculate area and volume. Then Archimedes continued Eudoxus’ idea and invented heuristic, the same with integration in order to calculate area. Even though the idea of who should take credit in discovering calculus is still unclear many people just credited both of them since they made their own discoveries independently that led us to what we know as calculus. Newton discovered the inverse relationship between the integral ( the area beneath the slope of a curve) and the derivative ( slope of the curve ), which made him consider as the creator of calculus. Newton idea of calculus is that the application of calculus were geometrical and is related to the physical world, such as describing the orbit of the moon around the earth. For Leibniz, calculus was more about understanding and analysis of change in graphs. Even though they are different from each other, Leibniz’s discovery was just as important as Newton’s.