Percentage Calculator

Percentage Calculator — How to Use It

This tool helps you solve common percentage questions instantly. First, pick what you want to calculate using “Choose an option”, then enter the numbers shown, and click Calculate.

Option 1: What is X% of Y

Use this when you want to find a percentage of a number.

Example: What is 20% of 150?

Steps

  1. Select What is X% of Y

  2. Enter X (percent) = 20

  3. Enter Y (number) = 150

  4. Click Calculate

Result: 30
(Because 20% of 150 = 30)

Option 2: X is what % of Y

Use this when you have two numbers and want to know what percent the first number is of the second.

Example: 30 is what percent of 120?

Steps

  1. Select X is what % of Y

  2. Enter X (number) = 30

  3. Enter Y (number) = 120

  4. Click Calculate

Result: 25%
(Because 30 is 25% of 120)

✅ Note: Y cannot be 0 (division by zero isn’t possible).

Option 3: % Increase

Use this when a value goes up and you want to know the percent change.

Example: Price went from 80 to 100.

Steps

  1. Select % Increase

  2. Enter Old value = 80

  3. Enter New value = 100

  4. Click Calculate

Result: 25% increase

✅ Note: Old value cannot be 0.

Option 4: % Decrease

Use this when a value goes down and you want to know the percent change.

Example: Value went from 200 to 150.

Steps

  1. Select % Decrease

  2. Enter Old value = 200

  3. Enter New value = 150

  4. Click Calculate

Result: -25%
(That’s a 25% decrease)

✅ Tip: If the result shows a negative percent, that means the value dropped.

Quick Tips

  • You can use decimals (example: 12.5%).

  • Results update only when you click Calculate.

  • Switching the dropdown will clear the old result so you don’t get confused.

     


Frequently Asked Questions

How do I calculate a percentage of a number?

Select “What is X% of Y”, enter the percentage (X) and the number (Y), then click Calculate. The tool will instantly show the result.

How do I find what percent one number is of another?

Choose “X is what % of Y”, enter both numbers, and click Calculate. The result will show the percentage value.

How do I calculate percentage increase?

Select “% Increase”, enter the old value and the new value, then click Calculate. The tool will show the percentage change.

How do I calculate percentage decrease?

Choose “% Decrease”, enter the original value and the new lower value, then click Calculate. The result will display the percentage decrease.

Can I use decimals in the calculator?

Yes. You can enter decimal values such as 12.5 or 99.99.

Why can’t I enter 0 as the old value?

The old value cannot be 0 because percentage change calculations require division by the original number.

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