How do I calculate X% of Y?

Convert the percentage to a decimal by dividing by 100, then multiply by the number. For example, 15% of 200 is (15 ÷ 100) × 200 = 0.15 × 200 = 30.

How do I find what percentage one number is of another?

Divide the part by the whole and multiply by 100. If you scored 42 out of 60, that is (42 ÷ 60) × 100 = 70%. The 'X is what percent of Y?' mode does this for you.

What is the difference between percentage increase and percentage difference?

Percentage increase (or decrease) measures change against the original value, so the order matters. Percentage difference measures the gap between two values against their average, so neither value is treated as the starting point — use it when comparing two independent numbers.

Why can't the starting value be zero for percentage change?

Percentage change divides by the original value, and dividing by zero is undefined. A change from 0 to any number is not a meaningful percentage — it is better described as an absolute increase.

Can I use negative numbers?

Yes, where the maths still makes sense. For example, you can calculate the percentage change from −20 to −5, or a percentage of a negative amount. The calculator will show a clear message instead of a broken result whenever a calculation is not defined.

How do I quickly estimate percentages in my head?

Find 10% by dividing by 10, then build from there: 5% is half of 10%, 20% is double, and 15% is 10% plus 5%. For 15% of 240, think 24 + 12 = 36.

Why does a 50% fall need a 100% rise to recover?

Because the base changes. If something drops from 100 to 50 (a 50% fall), getting back to 100 means adding 50 on top of the new base of 50 — and 50 is 100% of 50. Percentage moves are always measured against where you start.

Percentage Calculator

Work out X% of Y, what percent X is of Y, percentage increase, decrease and difference — instantly.

Under 15 seconds

Updated 20 Sept 2026

15% of 200

As a decimal: 0.15
Remaining part of Y: 170

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  src="https://calpaisa.com/embed/calculators/percentage-calculator/"
  width="100%"
  height="640"
  frameborder="0"
  loading="lazy"
  title="Percentage Calculator">
</iframe>

A percentage calculator answers the five everyday percentage questions: X% of Y (multiply Y by X÷100), X as a percentage of Y (divide X by Y, then ×100), percentage increase or decrease (change ÷ original ×100), and percentage difference (difference ÷ average ×100). Pick a mode, enter two numbers, and the result updates instantly.

Visual breakdown

How 15% of 200 compares with the rest of 200.

15% of Y

Rest of Y

Smart Insights

Generated from the numbers you entered — no guesswork.

15% of 200 is 30 — multiply 200 by 15 and divide by 100.

What is a percentage?

What the tool does, who it is for and what it cannot tell you.

A percentage is a way of expressing a number as a share of 100. The word literally means 'per hundred': 25% is 25 out of every 100, or one quarter. Percentages make it easy to compare proportions even when the underlying amounts are very different — a 10% discount means the same thing on a ₹500 purchase and a ₹5,00,000 one.

This calculator handles the five questions people ask most often: finding a percentage of a number, finding what percent one number is of another, working out a percentage increase, a percentage decrease, and the percentage difference between two values.

How does the Percentage Calculator work?

Each step the calculator runs, in plain language.

1
Pick the question you want answered
Choose from five modes: X% of Y, X as a percent of Y, percentage increase, percentage decrease, or percentage difference. The two inputs are always called X and Y.
2
Enter your two numbers
Decimals and large values work fine, and negative values are allowed where they make mathematical sense. Results update as you type.
3
Read the result with its steps
The headline answer appears instantly along with supporting values and a plain-language explanation of how it was reached.

What to enter in each field

The exact figure each input expects, so the result means what you think it means.

Calculation mode: Choose the question you want answered — for example 'What is X% of Y?' for discounts and tips, or 'Percentage increase' to compare an old and new price.
X (first value): In 'X% of Y' mode this is the percentage itself (enter 15 for 15%). In every other mode it is the first or original number.
Y (second value): In 'X% of Y' mode this is the base number you are taking a percentage of. In increase/decrease modes it is the new value; in 'what percent' mode it is the whole you are comparing against.

Percentage Calculator formula

The exact maths behind every number on this page.

X% of Y = (X ÷ 100) × Y · X as % of Y = (X ÷ Y) × 100 · % change = ((Y − X) ÷ X) × 100 · % difference = |X − Y| ÷ ((X + Y) ÷ 2) × 100

X: The first value — the percentage rate, or the starting number
Y: The second value — the base number, or the new number

Percentage change is measured against the original value; percentage difference is measured against the average of the two values, so neither is treated as the base.

Percentage Calculator calculation example

A ₹200 item is on sale at 15% off — how much do you save, and what do you pay?

1ModeWhat is X% of Y?
2Convert the percentage15 ÷ 100 = 0.15
3Multiply by the base0.15 × 200 = 30

15% of 200 is 30, so you save ₹30 and pay ₹170.

Important assumptions

What this calculation includes, and what it leaves out.

All calculations are pure arithmetic — no rounding is applied until the final display, which shows up to two decimal places.
Percentage change modes divide by the starting value X, so X cannot be zero; percentage difference divides by the average of the two values, so both cannot be zero.
Results are unit-free numbers — add your own currency, marks, or units when interpreting them.

Benefits

Why people use this calculator before signing a loan.

One tool for every percentage question
Discounts, tips, mark-ups, exam scores, growth rates — all five everyday calculations in one place.
Steps you can learn from
Every answer comes with the working, so you can see the method and do it yourself next time.
Handles awkward numbers
Decimals, very large values and negatives where mathematically valid — and a clear message instead of a broken result when something can't be calculated.

Financial tips

Practical guidance to act on your result.

For a quick mental estimate of 10% of anything, just divide by 10 — then scale up or down from there.
Percentage increase and decrease are not symmetric: going from 100 to 150 is a 50% increase, but coming back from 150 to 100 is only a 33.33% decrease.
Use percentage difference when neither number is the 'original' — for example comparing the prices of two different shops.
Check which mode you are in before reading the result — 'X is what percent of Y' and 'X% of Y' answer very different questions with the same two numbers.

Frequently asked questions

Short, direct answers to the questions we hear most.

Guides that explain how to use this calculation in a real decision.

Everyday & Math • 5 min read

How to Calculate Discount Percentage: Formula & Examples

Discount amount, final price and discount percentage — three formulas and worked examples.

Read guide

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Disclaimer

CalPaisa calculators are for general information and planning only. Results are estimates based on the values you enter and standard formulas, and may differ from the figures your bank, employer, or tax authority applies. Nothing here is investment, tax, or legal advice. Please confirm important decisions with a qualified professional. Read our financial disclaimer, learn how CalPaisa works, or tell us about a calculation you think is wrong.

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