## %Percentage Change Calculator

##### Percent change calculator uses this formula:

((v2 - v1) / v1)*100 your percent change. v1 is the original value, and v2 is the value it changed to.

## How can I calculate a percentage change ?

### Calculating percentages using a calculator

###### Here is a warning about using the percentage button on a calculator: the result depends on when you press the % button in your calculation. Sometimes it has no effect, sometimes it seems to divide by 100, and at other times it multiplies by 100. Here are some examples
• Pressing 48÷400% gives an answer of 12. Now 48÷400 = 0.12, so pressing the % button has had the effect of multiplying by 100. This has found 48 as a percentage of 400.
• Pressing 1 ÷ 2 × 300% gives the answer 1.5. Now 1 ÷ 2 × 300 = 150, so pressing the % button here has divided by 100. This has found 300% of a half.
• Pressing 400 × 50% gives an answer of 200. Now 400 × 50 = 20, 000, so pressing % here has divided by 100. This has found 50% of 400.
• Pressing 50% × 400 results in 400 on the display, requiring = to be pressed to display an answer of 20,000. So pressing the % button here has had no effect.

### Percentage Change Error

The percent error is used in many scientific applications. In labs, it measures how accurate an experiment is, compared to the expected (often numerical) outcome.

Calculating percentage change and expressing an increase or decrease. ( ΔV / |V1| ) * 100 = ((V2 - V1) / |V1|) * 100 = percentage change.