How do you calculate a percentage increase?

Calculate a percentage increase by subtracting the old value from the new one, dividing the difference by the old value and then multiplying the quotient by 100. You need the new and old value.

1. Calculate the difference between the two values

   Subtract the old value from the new value. If the old value is 60 and the new value is 90, then the difference is 90 minus 60, or 30.

2. Find the quotient of the difference of the two values and the old value

   Divide the difference of the two values by the old value. For the old value 60 with the difference of 30 from the new value, the quotient of the two is 30/60, or 1/2

3. Calculate the percentage increase

   Multiply the quotient by 100. This is the percentage difference. For the quotient of the old value and the difference between the two values 1/2, the percentage difference is 1/2 times 100, or 50 percent.