Percentage & Ratio Calculator

The percentage as a plain number: enter 15 for 15%. It may be over 100 or negative where that makes sense.

The base amount that the percentage is taken of. Example: 15% of 80 is 12.

The first value. Its role depends on the mode: the part in “a is what % of b”, the known part in “a is p% of what”, the starting value for % change, or the first term of the ratio and proportion.

The second value: the whole in “a is what % of b”, the ending value for % change, or the second term of the ratio and proportion.

The third value of the proportion a/b = c/x. The tool solves for the missing x so that both sides are equal.