Percentage Calculator

How to Use the Percentage Calculator

This calculator offers three modes accessible via tabs at the top. In the first tab, enter a percentage and a number to find what that percentage of the number is. In the second tab, enter two numbers to determine what percent the first number is of the second. In the third tab, enter an original value and a new value to calculate the percentage change between them. All calculations happen in real time as you type, and the formula used is displayed below the result for learning purposes.

How Percentage Calculations Work

A percentage represents a fraction of 100. To find X% of Y, multiply Y by X and divide by 100. To determine what percent X is of Y, divide X by Y and multiply by 100. The percentage change formula subtracts the old value from the new value, divides by the absolute value of the old value, and multiplies by 100. A positive result indicates an increase while a negative result indicates a decrease. Each formula is displayed alongside the result so you can verify and learn the mathematics behind the calculation.

Practical Tips

• Use the percentage of a number mode for discounts. Enter the discount percentage and the original price to instantly see the savings amount.
• The percentage change mode is helpful for comparing financial data like month-over-month revenue growth or year-over-year price changes.
• When calculating grades, use the second tab to find what percentage your score represents of the total possible points.
• All results are rounded to two decimal places. For more precision in scientific applications, use the displayed formula with a dedicated math tool.

Frequently Asked Questions

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 20% of 150 equals 150 times 20 divided by 100, which is 30.

What is the formula for percentage change?

Percentage change equals the new value minus the old value, divided by the absolute value of the old value, times 100. A positive result means increase, negative means decrease.

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

Divide the part by the whole and multiply by 100. For example, 30 is what percent of 150? 30 divided by 150 times 100 equals 20%.

What is the difference between percentage increase and decrease?

Both use the same formula. When the new value is larger than the original, the result is positive (increase). When the new value is smaller, the result is negative (decrease).

Can percentages be greater than 100?

Yes. A percentage above 100% means the value exceeds the reference amount. For example, 200% of 50 is 100, meaning the result is double the original number.