Percentage Calculator
Quickly calculate percentages, percentage change, and percentage of a total.
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How to use this calculator
Multiply your number by the percentage and divide by 100.
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Enter the number you want to find a percentage of.
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Enter the percentage you want to calculate.
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The result appears instantly below the inputs.
Frequently asked questions
How do I calculate 20% of a number?
Enter the number in the first field and 20 in the percentage field. The calculator multiplies the number by 20 and divides by 100.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 out of 200 is (30 ÷ 200) × 100 = 15%.
What is percentage change?
Percentage change = ((New Value − Old Value) ÷ Old Value) × 100. A positive result is an increase; negative is a decrease.
What is a percentage?
How to use the percentage
This percentage gives you instant, accurate results — no registration or download required. Enter your values above and get your result in seconds. The tool is free, works on all devices, and keeps your data private — nothing is stored or shared.
How the percentage works
The percentage uses standard formulas used in financial planning, budgeting, and investment decisions. Enter your inputs, and the tool calculates the result instantly in your browser. No server-side processing means your data stays on your device. Results update in real time as you change inputs.
How percentages work
A percentage is a way of expressing a number as a fraction of 100. The word comes from the Latin "per centum," meaning "by the hundred." Percentages are used everywhere — from bank interest rates and tax calculations to discounts and exam scores.
Common percentage formulas
To find X% of Y: multiply Y by X and divide by 100. To find what percentage X is of Y: divide X by Y and multiply by 100. To calculate percentage change: subtract the old value from the new, divide by the old value, and multiply by 100.
Practical uses
Percentage calculators are used by students checking grades, shoppers comparing discounts, investors tracking portfolio returns, and businesses measuring growth. Understanding percentages is one of the most universally useful mathematical skills.
Percentage: how it works
Built on well-established mathematical principles, this tool delivers accurate results for students, researchers, and professionals. Enter your values and get instant clarity without specialist software or manual arithmetic.
Who uses this tool?
Teachers, students, engineers, and data analysts use it to verify calculations, check homework, and solve problems faster. It is intuitive enough for beginners while comprehensive enough for professional use.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →