Calculate percentages instantly — find X% of a number, what percentage X is of Y, or the percentage change between two values. Free online percentage calculator.
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Percentage Calculator
Our percentage calculator provides three essential calculation modes in one convenient tool. Whether you need to find a percentage of a number, determine what percentage one number is of another, or calculate the percentage change between two values, you get instant results with no registration required.
Formulas
Finding X% of a number: multiply Y by X and divide by 100. For example, 25% of 80 = 80 × 25 / 100 = 20.
What percentage X is of Y: divide X by Y and multiply by 100. If you scored 42 out of 50, that is 42 / 50 × 100 = 84%.
Percentage change: ((New − Old) / |Old|) × 100. If a stock went from €50 to €65: ((65−50)/50) × 100 = 30% increase.
Key Distinction
This is a common source of confusion. Percentage is a relative measure, while percentage points are absolute. If an interest rate goes from 5% to 7%, it increased by 2 percentage points, but by 40% in relative terms (2/5 × 100 = 40%).
News headlines often mix these up, so understanding the distinction helps you interpret financial information correctly. Use our{' '} mortgage calculator{' '} to see the real impact of interest rate differences.
Personal Finance
A 1% difference in your mortgage rate on a €200,000 loan over 25 years costs approximately €27,000 more in total interest. If your portfolio returns 7% annually versus 5%, on €50,000 invested for 20 years that difference equals over €60,000.
At 2.5% annual inflation, €100 today will have the purchasing power of only €78 in 10 years. A 3% raise on a €2,000/month salary adds €720/year.
Mental Math Tips
10%
Move the decimal point one place to the left. 10% of 250 = 25.
5%
Find 10% and halve it. 5% of 250 = 12.5.
25%
Divide by 4. 25% of 250 = 62.5.
50%
Divide by 2. 50% of 250 = 125.
1%
Move the decimal two places left. 1% of 250 = 2.5.
Any %
Combine the above: 15% = 10% + 5%, 30% = 3 × 10%.
To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 = 200 × 15 / 100 = 30. Our calculator does this instantly — just enter the percentage and the number.
To find what percentage X is of Y, divide X by Y and multiply by 100. For example, 30 is what % of 200? 30 ÷ 200 × 100 = 15%. Use our 'X is what % of Y?' tab for instant results.
Percentage change = ((New - Old) / |Old|) × 100. For example, change from 100 to 150 = ((150-100)/100) × 100 = 50% increase. Change from 200 to 150 = ((150-200)/200) × 100 = -25% decrease.
A percentage is relative, while percentage points are absolute. If an interest rate goes from 5% to 7%, it increased by 2 percentage points but by 40% (2/5 × 100). This distinction is important in financial contexts.
Quick mental math tricks: 10% = move decimal one place left. 5% = half of 10%. 25% = divide by 4. 50% = divide by 2. 1% = move decimal two places left. Combine these for any percentage: 15% = 10% + 5%, 30% = 3 × 10%.