Percentage Calculator
Calculate percentages instantly. Find what percent one number is of another, calculate percentage increase or decrease, and more — all free, no signup required.
What is X% of Y?
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X is what percent of Y?
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Percentage Increase / Decrease Calculator
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Increase / Decrease a Number by a Percentage
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Percentage Difference Between Two Numbers
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What is X% More / Less Than Y?
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How to Calculate Percentages
Finding a percentage of a number
Multiply the number by the percentage, then divide by 100. Example: 20% of 500 = (20 × 500) ÷ 100 = 100.
Finding what percentage X is of Y
Divide X by Y, then multiply by 100. Example: 15 is what % of 60? → (15 ÷ 60) × 100 = 25%.
Percentage increase or decrease
Subtract original from new, divide by the original, multiply by 100. Example: 80 → 100 = ((100 − 80) ÷ 80) × 100 = 25% increase.
Percentage difference
Divide the absolute difference by the average of the two values, then multiply by 100. Example: difference between 40 and 60 = |40−60| ÷ ((40+60)÷2) × 100 = 40%.
How to use Percentage Calculator
- 1Choose a calculator type
Scroll to the section that matches what you need — finding a percentage of a number, calculating percentage change, finding percentage difference, and more.
- 2Enter your numbers
Type values into the input fields. Results update in real time as you type — no need to press a button.
- 3Read the formula
Below each result, you'll see the exact formula used (e.g. '(20 ÷ 100) × 500 = 100') so you understand the math.
- 4Expand step-by-step explanation
Click 'Show steps' under any result to see a plain-English breakdown of the calculation — useful for learning or double-checking your work.
- 5Copy the result
Click the copy button next to any result to copy the answer to your clipboard instantly.
Frequently Asked Questions
What is a percentage?
- A percentage is a way of expressing a number as a fraction of 100. The word 'percent' comes from the Latin 'per centum', meaning 'by the hundred'. For example, 25% means 25 out of every 100, or 0.25 as a decimal.
How do I calculate what percent X is of Y?
- Divide X by Y, then multiply by 100. For example, to find what percent 15 is of 60: (15 ÷ 60) × 100 = 25%. Use the 'X is what percent of Y?' calculator on this page for instant results.
What is the difference between percentage change and percentage difference?
- Percentage change measures how much a value has increased or decreased from a starting point — it has a direction (increase or decrease). Percentage difference measures the relative difference between two values without implying a direction — it's the absolute difference divided by the average of the two values, expressed as a percentage.
Can I calculate a percentage of a negative number?
- Yes. The calculators on this page accept negative numbers. For example, 20% of -500 is -100, and the percentage change from -80 to -100 is -25% (a decrease). The formulas work correctly for negative inputs.
What does 'percentage increase' mean?
- A percentage increase tells you by how much a value has grown relative to its original value. Formula: ((New Value − Original Value) ÷ Original Value) × 100. For example, a price rising from 80 to 100 is a 25% increase because (100 − 80) ÷ 80 × 100 = 25.
Is this calculator accurate?
- Yes. All calculations are performed using standard floating-point arithmetic in JavaScript and display up to 10 significant figures. For everyday percentage calculations the results are exact. Very large numbers (above 10^15) may have minor floating-point rounding, which the tool flags with a warning.