How to Calculate Percent Change
To find a percent change, first work out the difference between the two numbers you are comparing. Then, divide that number by the original number and multiply the answer by 100.
Percent Change is found by taking the original amount, minus the new amount, finding the absolute value of that, dividing that number by the original amount, and then finally multiplying by 100. When you divide these two values, you’re going to get a decimal so to get our percent change we have to multiply by 100.
Let’s look at a sample problem. If a pair of pants cost 24 dollars last week and were marked up to 30 dollars this week, what is the percent change? We’re going to use our percent change formula to find it. Now, this percent change would be a percent increase since we went up from 24 dollars originally to 30 dollars.
If it had been reversed, say the pair of pants cost 30 dollars last week and only 24 this week, that would be a percent decrease. For this problem we’re doing an increase. My percent change, or percent increase in this case, is the absolute value the original amount minus the new amount.
The absolute value of the original amount, 24, minus new amount, 30, divided by the original amount, which is 24, and then we have to multiply this times 100 to achieve our percent. 24 minus 30 is negative 6, you can add the inverse to find that. The absolute value of negative 6 is 6. Absolute value is distance from 0, so that 6 out of 24, times 100 and 6 divided by 24 is 25 hundredths. 25 hundred times 100 would give us a percent increase of 25 percent.