Percentage Calculator
Free online percentage calculator. Compute X% of Y, find what percent X is of Y, calculate percentage change, and increase or decrease values by a percentage.
What is X% of Y?
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What Is a Percentage Calculator?
A percentage calculator is a tool that performs common percentage-related math operations. It supports four calculation modes: finding a percentage of a value, determining what percentage one number is of another, computing the percentage change between two values, and increasing or decreasing a number by a given percentage. All results are computed instantly in the browser with no rounding errors.
How to Use the Percentage Calculator
- Select a calculation mode from the tabs: X% of Y, X is what % of Y, % Change, or % Increase/Decrease.
- Enter the required numbers in the input fields.
- The result is calculated live as you type.
- Click the copy button to copy the result to your clipboard.
Common Use Cases
- Discounts & Sales Tax — Quickly calculate sale prices, discount amounts, or tax totals when shopping or preparing invoices.
- Financial Analysis — Determine percentage change in revenue, profit margins, or investment returns over time.
- Tip Calculation — Figure out how much to tip at a restaurant by calculating a percentage of the bill.
- Grade & Score Conversion — Convert raw scores to percentages or determine what fraction of total points were earned.
FAQ
How accurate are the results?
Results use JavaScript floating-point arithmetic with up to 12 significant digits of precision, which is more than sufficient for everyday percentage calculations.
What does percentage change mean?
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Can I enter negative numbers?
Yes. All four modes accept negative numbers. For percentage change, the absolute value of the original number is used as the denominator to handle negative starting values correctly.
What is the difference between percentage increase and percentage change?
Percentage increase/decrease applies a known percentage to a value to get a new result (e.g., 200 + 15% = 230). Percentage change calculates the percentage difference between two known values (e.g., from 200 to 230 = 15% increase).