The percentage increase calculator above computes an increase or decrease of a specific percentage of the input number. It basically involves converting a percent into its decimal equivalent, and either subtracting (decrease) or adding (increase) the decimal equivalent from and to 1, respectively. Multiplying the original number by this value will result in either an increase or decrease of the number by the given percent. Refer to the example below for clarification., For example, 35% is equivalent to the decimal 0.35, or the fractions . Percentages are computed by multiplying the value of a ratio by 100. For example, if 25 out of 50 students in a classroom are male, . The value of the ratio is therefore 0.5, and multiplying this by 100 yields: 0.5 × 100 = 50., To evaluate the percentage increase or decrease between two numbers, we subtract the old from the new value, divide the result by the old value, and then multiply it by 100. A percentage calculator simplifies these calculations by taking user inputs, applying suitable formulas, and providing instant results..