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The Percentage Change Calculator will quantify the change from one number to another and express the change as an increase or decrease. This calculator will be most commonly used when there is an “old” and “new” number or an “initial” and “final” value. A positive change is expressed as an increase amount of the percentage value while a negative change is expressed as a decrease amount of the absolute value of the percentage value.

You will generally use the percent change calculation when the order of the numbers does matter; you have starting and ending values or an "old number" and a "new number". When you are just comparing 2 numbers you may want to use the percent difference formula and calculation.

Related calculations can be done with Percentage Calculator and conversions can be solved with Decimal to Percent, Percent to Decimal, Fraction to Percent, or Percent to Fraction.

Percentage change equals the change in value divided by the absolute value of the original value, multiplied by 100.

**Percentage change = ( ΔV / |V _{1}| ) * 100 = ((V_{2} - V_{1}) / |V_{1}|) * 100**

For **example one**, to calculate the percentage change:

- What is the percentage change expressed as an increase or decrease for 3.50 to 2.625?
- Let V
_{1}= 3.50 and V_{2}= 2.625 and plug numbers into our formula ((V_{2}- V_{1}) / |V_{1}|) * 100 - ((2.625 - 3.50) / |3.50|)*100
- = (-0.875 / 3.50) * 100
- = -0.25 * 100
- = -25% change

Saying a -25% change is equivalent to stating a 25% decrease.

Note that if we let V

_{1}= 2.625 and V_{2}= 3.50 we would get a 33.3333% increase. This is because these percentages refer to different amounts. 25% of 3.50 and 33.3333% of 2.625. Both are equal to our difference of 0.875.

As a **second example** let's look at a change that includes negative numbers and taking the absolute value of V_{1} in the denominator makes a difference.

- What is the percentage change expressed as an increase or decrease for -25 to 25?
- Let V
_{1}= -25 and V_{2}= 25 and plug numbers into our formula ((V_{2}- V_{1}) / |V_{1}|) * 100 - ((25 - -25) / |-25|)*100
- = (50 / 25) * 100
- = 2 * 100
- = 200% change

Saying a 200% change is equivalent to stating a 200% increase.

As a **third and final example** let's look at another change that includes negative numbers and taking the absolute value of V_{1} in the denominator makes a difference.

- What is the change expressed as an increase or decrease for -25 to -50?
- Let V
_{1}= -25 and V_{2}= -50 and plug numbers into our formula ((V_{2}- V_{1}) / |V_{1}|) * 100 - = ((-50 - -25) / |-25|) * 100
- = (-25 / 25) * 100
- = -1 * 100
- = -100% change

Saying a -100% change is equivalent to stating a 100% decrease.

Wikipedia contributors. "Percent difference: percent change" Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, last visited 18 Feb. 2011.

Percent Change, Increase, Difference from Dr. Math, last visited 22, Feb. 2011.

**Cite this content, page or calculator as:**

Furey, Edward "Percentage Change Calculator" From *http://www.CalculatorSoup.com* - Online Calculator Resource.