An amount per 100 that refers to a portion of a whole (in a general way) typically without using a specific number. In mathematics, a percentage is a number or ratio that represents a fraction of 100. It is often denoted by the symbol "%" or simply as "percent" or "pct." For example, 45% is equivalent to the decimal 0.45, or the fraction 45/100.

It is a calculator or tool that uses the percentage formula to solve for the desired value in that formula. The percentage formula contains three variables. If any two of the variables are known, the third variable can be calculated.

Although the percentage formula can be written in different forms, it is essentially an algebraic equation involving three values.

P × V1 = V2

P is the percentage, V1 is the first value that the percentage will modify, and V2 is the result of the percentage operating on V1.