# Percentage Decrease Calculator

Table of Contents:

**Percentage Decrease Formula**

**Percentage decrease = {FirstValue – SecondValue / FirstValue} * 100**

Percentage decrease calculator calculates percentage by subtracting the second value from the first value, which is known as calculating decrease. After subtracting value 2 from value 1 the answer is then divided by first value and multiplied by 100.

**Example:**

Suppose your study table lamp is of a 40-watt ordinary light bulb. That means your lamp consumes 40 watts of energy in an hour. If you changed the ordinary light bulb with an energy saver that uses 8 watts of electricity per hour. So the difference in energy consumption could me measure by using percentage decrease calculator.

**Percentage decrease = {FirstValue – SecondValue / FirstValue} * 100**

40 – 8 = 32

32 / 40 = 0.8

0.8 * 100 = 80%

**Conclusion**

You could save 80% of energy by switching an ordinary light bulb with an energy saver.

**Example 2:**

A rectangle having sides of length a = 6 and b = 4. Let suppose somehow the length of rectangle is decreased from point 6 to 5. Before decreasing the unit of rectangle was 24 but now it is been decreased to 20. So the difference is of 4 points. We can calculate the difference by percentage change calculator.

**Percentage decrease = {FirstValue – SecondValue / FirstValue} * 100**

24 – 4 = 20

20 / 24 = 0.833

0.833 * 100 = 83.33