How to Calculate a Percent Change in Mass

The percent change formula is difficult to remember and easily reversed, so it is always good to be sure you aren't reversing any values or using an incorrect formula. Percent change is generally used for both reporting results and goal setting. It is an effective way to compare two changes with different starting values, and is far superior to just comparing numerical changes.

Things You'll Need

• Calculator

Instructions

Calculating Percent Change in Mass

1. Establish your starting value and write it down. Say, for example, your starting value is 200 units.

2. Establish your final value. To continue our example, say the final value in this case is 180 units.

3. Subtract the final value from the starting value, label it as "change." Using the examples from steps 1 and 2, step 3 would be 200 units -180 units = 20 units.

4. Calculate percent change by dividing "change" by the starting value then multiply the result by 100. Finishing the example from steps 1-3, this would appear as:
   (20 units / 200 units) x 100 = 10.0 %

Tips & Warnings

• Round to desired significant figures only after obtaining your final answer.

References

• Percent Change Formula