Question 1

How do I calculate a percentage of a number?

Accepted Answer

Multiply the number by the percent as a decimal: percent_of = base * (percent/100).

Question 2

How do I find what percent one number is of another?

Accepted Answer

Divide part by whole and multiply by 100: percent = (part/whole)*100.

Question 3

How do I compute percentage change?

Accepted Answer

Use ((new - old) / old) * 100%. The base is the original value.

Question 4

Why do my results look off?

Accepted Answer

Check whether you used the correct base and converted the percent to a decimal.

Question 5

How do I reverse a percentage increase/discount?

Accepted Answer

Divide by (1 + p) for increases or by (1 - p) for discounts to recover the original.

Percentage Calculator