Math Example: How to calculate percentage increase, Decrease or Difference How to calculate percent increase between two numbers? To calculate percent difference, you need to follow these steps: Percent Problem: You need to calculate percent % increase from 2 to 10. First Step: find the difference between two numbers, in this case, it’s 10 – 2 = 8. Second Step: Take the difference, 8, and divide by the original number: 8/2 = 4. Last, multiply the number above by 100: 4*100 = 400%. You’re done! You calculated difference of a number in percent, and the answer is a percentage increase of 400%