Percentage Calculator
This free percentage calculator finds a percent of a number, a percentage change, an increase or decrease, and the original value. Moreover, the result updates as you type, so you can check any sum in seconds.
Enter two numbers to see the answer.
How to Use the Percentage Calculator
- Choose the tab that matches your question.
- Type two numbers into the boxes. For the increase tab, also pick Increase or Decrease.
- Read the result and the working below it.
- Switch tabs whenever you need a different type of percentage problem.
What Is a Percentage Calculator?
A percentage calculator is a tool that works out parts of 100 for you. Therefore, you do not need to remember formulas or do long division by hand. People use it to find a tip, to compare marks, to check a salary rise or to read a business report.
It is also handy when you shop. For example, you can use it to see how much a price changed, and then try our Discount Calculator to find the final sale price. For more free tools, visit our CalcPro home page or the full list of math calculators.
Percentage Calculator Formulas
Every tab uses one simple rule. In addition, you can use the same formulas on paper to check any answer.
Percentage Calculator Examples
These worked examples show how each tab gives its answer. Try them in the calculator above.
80 × 15 ÷ 100
= 12
30 ÷ 150 × 100
= 20%
(100 − 80) ÷ 80 × 100
= 25% increase
20 ÷ 0.25
= 80
Quick Mental Tricks for Percentages
Sometimes you can skip the calculator. Instead, use these shortcuts for fast estimates.
- 10%Move the decimal point one place to the left.
- 50%Divide the number by 2.
- 25%Divide the number by 4.
- 1%Divide the number by 100.
For a deeper explanation of how percentages work, see Wikipedia’s percentage article or the lesson on Math Is Fun.
Percentage Calculator FAQ
How do I calculate a percentage?
Divide the part by the whole, then multiply by 100. For example, 30 out of 150 is 30 ÷ 150 × 100, which equals 20%. The percentage calculator above does this in the “What %” tab.
How do I calculate a percentage increase or decrease?
Subtract the old value from the new value, divide by the old value, then multiply by 100. A positive answer is an increase, and a negative answer is a decrease. For example, going from 80 to 100 is a 25% increase.
How do I find a percent of a number?
Multiply the number by the percentage, then divide by 100. For example, 15% of 80 is 80 × 15 ÷ 100, which equals 12.
What is the difference between percentage change and percentage points?
A percentage point is the plain gap between two percentages, while percentage change compares the gap with the starting value. For example, a rate that moves from 10% to 12% rises by 2 percentage points, but it is a 20% increase.
Is this percentage calculator free?
Yes. It is free, it needs no account, and it works on phones, tablets and computers.
The results are for general information. Please check important figures, such as prices, taxes or grades, before you use them.