Percentage Calculator
Three of the most common percentage questions, answered instantly — no need to visit three different pages.
What is X% of Y?
25% of 500 = 125
X is what percentage of Y?
50 is 25% of 200
Percentage increase or decrease
Increase of 20%
How to use the Percentage Calculator
Pick the card that matches your question. Type your numbers into the two fields in that card and the result updates instantly — there’s no separate calculate button and no need to reload the page.
What is a percentage calculator?
A percentage calculator handles the three questions people ask about percentages most often: finding a percentage of a number, finding what percentage one number is of another, and finding how much a number has increased or decreased in percentage terms. This tool covers all three on a single page.
How each calculation works
Every percentage calculation ultimately reduces to a simple ratio. “X% of Y” scales Y down by X out of 100. “X is what % of Y” turns the ratio X/Y into a percentage. “Percentage change” compares the gap between two numbers to the original number, to express that gap as a percentage.
Formulas
- X% of Y:
(X ÷ 100) × Y - X is what % of Y:
(X ÷ Y) × 100 - Percentage change:
((New − Original) ÷ Original) × 100
Worked example
A product’s price rises from ₹500 to ₹600. The change is ((600 − 500) ÷ 500) × 100 = 20%, so the price increased by 20%.
Understanding your result
A positive percentage change means the new value is higher than the original; a negative result means it’s lower. For “X% of Y”, the result is a plain number in the same units as Y (for example, rupees of a price, or marks out of a total).
Factors that affect the result
These are pure arithmetic calculations, so the result depends only on the numbers you enter. The one thing to double-check is which number is the “original” and which is the “new” value in the increase/decrease card — swapping them flips the sign of the result.
Common uses
People use this calculator for working out discounts and sale prices, checking exam or survey scores, comparing a salary hike or price rise year-on-year, splitting a bill with a tip percentage, or verifying a GST-style tax calculation by hand.
Important notes
All three calculators accept negative numbers where mathematically valid, and the “of value” in card two cannot be zero, since dividing by zero has no defined percentage.
Frequently asked questions
What is a percentage calculator used for?
It's used for any quick percentage math — discounts, tax, score conversions, salary or price changes — without doing the arithmetic by hand.
How do I calculate what X% of Y is?
Divide X by 100, then multiply by Y. For example, 25% of 500 is (25 ÷ 100) × 500 = 125.
How do I find what percentage one number is of another?
Divide the first number by the second, then multiply by 100. For example, 50 out of 200 is (50 ÷ 200) × 100 = 25%.
What's the difference between percentage and percentage points?
A percentage change is relative to the original value (e.g. 500 → 600 is a 20% increase). Percentage points are a simple difference between two percentages (e.g. 40% → 50% is a 10-point increase, but a 25% relative increase).
Can I use negative numbers?
Yes, all three calculators accept negative values where mathematically valid.
Why can't the 'of value' be zero?
Dividing by zero doesn't produce a defined result, so the second calculator needs a non-zero denominator to work.
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