Percentage Calculator Calculate a percent of a value before and after, or find the percentage change between two values, and see how to calculate each one. Examples: Apply 10% to 100, and see how each value was calculated Try 12.5% of 50: the "50 less 12.5%" value is 43.75. Then try 12.5% of 43.75 (shows that before a 12.5% reduction it was 50.)
Let's say the question is: What is 10% of 200?. Here's how to do it: Change the percentage figure into a decimal by dividing the figure by 100. So, 10% becomes 10/100 = 0.1. Multiply the decimal figure by the full amount. So, 0.1 x 200 = 20. This gives you your answer. 10% of 200 is 20. The formula for this calculation looks like this: