Percentages are one of several ways of describing quantities' relationships to one another. Specifying one number as a percentage of another means specifying the fraction of the second quantity the first comprises. The percentage value is the number that, divided by 100, equals that fraction. To express the percentage as a whole number, round it accordingly. Some applications, however, don't require percentages as exact whole figures.
Divide the first number the second. For instance, if you want to find what percentage 43 is out of 57, divide 43 by 57 to get 0.754386.
Multiply the result by 100 -- 0.754386 x 100 = 75.4386.
Round the result. To produce a whole number, round it to two significant figures, stating that, with this example, 43 is 75 percent of 57. To provide a slightly more accurate answer, round it to two decimal places, stating that 43 is 75.44 percent of 57.