Our free percentage calculator makes it easy to calculate percentages, percentage changes, increases, decreases, and percentage differences. Enter your values, choose the type of calculation you need, and get an instant result with the calculation shown step by step.
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Percentage Calculator
Calculate percentages quickly and easily.
How to Use a Percentage Calculator
Using the calculator is simple. First, choose the type of percentage calculation you need. Enter the requested values in the fields provided and select Calculate.
The calculator will display the result together with the formula used to obtain it.
You can use it to find a percentage of a number, determine what percentage one number is of another, calculate percentage change, work out a percentage increase or decrease, or compare two values using percentage difference.
How to Calculate a Percentage
A percentage expresses a number as a fraction of 100.
To calculate a percentage of a number, divide the percentage by 100 and multiply it by the number.
For example, to calculate 15% of 250:
15 ÷ 100 × 250 = 37.5
Therefore, 15% of 250 is 37.5.
The basic formula is:
Percentage ÷ 100 × Number = Result
Different percentage questions require different formulas. The sections below explain the most common calculations.
You can also learn more about basic mathematical concepts and formulas from Math Is Fun
Percentage Calculator Formulas
What Is X% of Y?
Use this calculation when you know a percentage and a number and want to find the corresponding value.
Formula:
X ÷ 100 × Y
For example:
20% of 150
20 ÷ 100 × 150 = 30
Therefore, 20% of 150 is 30.
What Percentage Is X of Y?
Use this calculation when you know a part and a whole and want to determine what percentage the part represents.
Formula:
X ÷ Y × 100
For example:
30 is what percentage of 150?
30 ÷ 150 × 100 = 20%
Therefore, 30 is 20% of 150.
X Is X% of What?
Use this calculation when you know the part and the percentage but want to find the whole number.
Formula:
X ÷ (Percentage ÷ 100)
For example:
30 is 20% of what number?
30 ÷ (20 ÷ 100) = 150
Therefore, 30 is 20% of 150.
Percentage Change
Percentage change measures how much a value has changed compared with its original value.
The formula is:
(New Value − Original Value) ÷ |Original Value| × 100
For example, if a value changes from 100 to 125:
(125 − 100) ÷ 100 × 100 = 25%
The percentage change is 25%.
If the new value is lower than the original value, the result is negative. For example:
100 → 75
(75 − 100) ÷ 100 × 100 = −25%
This represents a 25% decrease.
Percentage Increase and Decrease
Percentage increases and decreases are useful when comparing prices, quantities, measurements, salaries, populations, and other values.
Percentage Increase
To increase a value by a given percentage:
Original Value × (1 + Percentage ÷ 100)
For example, increasing 100 by 25%:
100 × (1 + 25 ÷ 100) = 125
The new value is 125.
Percentage Decrease
To decrease a value by a given percentage:
Original Value × (1 − Percentage ÷ 100)
For example, decreasing 100 by 25%:
100 × (1 − 25 ÷ 100) = 75
The new value is 75.
Percentage Difference
Percentage difference is useful when comparing two values without treating either value as the original.
The formula is:
|A − B| ÷ ((A + B) ÷ 2) × 100
For example, to compare 100 and 120:
|100 − 120| ÷ ((100 + 120) ÷ 2) × 100
20 ÷ 110 × 100 = 18.18%
Therefore, the percentage difference between 100 and 120 is approximately 18.18%.
Percentage Change vs. Percentage Difference
Percentage change and percentage difference are related, but they answer different questions.
Percentage change compares a new value with an original value. It is useful when something increases or decreases over time.
For example:
100 → 125 = 25% change
Percentage difference compares two values without designating either one as the starting point. It uses the average of the two values as the reference.
For example:
100 and 120 = 18.18% difference
Choosing the correct calculation is important because the two formulas produce different results.
Percentage Calculator Examples
What Is 10% of 200?
10 ÷ 100 × 200 = 20
Answer: 20
What Is 25% of 80?
25 ÷ 100 × 80 = 20
Answer: 20
40 Is What Percentage of 200?
40 ÷ 200 × 100 = 20%
Answer: 20%
What Is a 20% Increase From 150?
150 × (1 + 20 ÷ 100) = 180
Answer: 180
What Is a 20% Decrease From 150?
150 × (1 − 20 ÷ 100) = 120
Answer: 120
Frequently Asked Questions
What Is a Percentage?
A percentage expresses a number as a fraction of 100. The percentage symbol is %.
How Do I Calculate a Percentage of a Number?
Divide the percentage by 100 and multiply it by the number.
For example:
20% of 150 = 20 ÷ 100 × 150 = 30
How Do I Calculate Percentage Increase?
Subtract the original value from the new value, divide the result by the original value, and multiply by 100.
You can also use the Percentage Change calculation in our calculator.
How Do I Calculate Percentage Decrease?
Subtract the new value from the original value, divide the result by the original value, and multiply by 100.
The result indicates how much the value has decreased relative to the original value.
What Is the Difference Between Percentage Change and Percentage Difference?
Percentage change uses an original value as the reference point.
Percentage difference compares two values using their average as the reference.
Can I Calculate Percentages With Decimal Numbers?
Yes. The calculator accepts decimal values, so you can calculate percentages using numbers such as 12.5, 37.5, or 125.75.
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