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Percentage Calculator: Find Percent Of, Change and More

This free percentage calculator answers the five questions people ask most: what is X% of Y, X is what percent of Y, the percent change between two numbers, and a number increased or decreased by a percentage.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

A percentage is a number written as a part of 100. We use percentages for discounts, tax, interest, exam marks, tips, test results and growth in sales or prices. The sums are simple, but it is easy to mix up which number to divide by.

This calculator has five modes so that the question you have in mind matches the mode you pick. It also prints the working, so you can check the steps or copy them into a report.

How to Use This Tool

  1. Choose the question from the list, such as What is X% of Y?.
  2. Type the two numbers. Commas are allowed, so 1,250 works.
  3. Press Calculate.
  4. Read the big answer on top and the working below it.

How the Calculation Works

Percent of a number: result = X ÷ 100 × Y. What percent: result = X ÷ Y × 100. Percent change: result = (Y − X) ÷ |X| × 100. Increase: Y × (1 + X ÷ 100). Decrease: Y × (1 − X ÷ 100).

The calculator keeps up to twelve significant digits and trims trailing zeros, so 0.1 + 0.2 style rounding noise does not show.

Worked Example

A shop marks a coat at 2,400 rupees and offers 15% off. Choose Decrease Y by X%, enter 15 and 2400. The answer is 2,040. The saving is 15% of 2,400, which is 360.

To see how much a price rose, pick % change and enter 80 and 92. The change is +15%.

Common Uses

  • Discounts, sales tax, GST and tips.
  • Marks and grades: 42 out of 60 is 70%.
  • Growth in traffic, sales, salary or prices.
  • Interest and loan rates when you only need a quick share of a total.

Tips and Common Mistakes

  • Always check which number is the base. In % change from X to Y, X is the starting value.
  • A percent change cannot be worked out from a starting value of zero.
  • To undo a 20% increase, decrease by 16.67%, not 20%.

Next, you may need the fraction calculator, average calculator, percent error calculator, ratio calculator.

Everything runs in your browser. Nothing you type is uploaded, stored or sent to any outside service.

Frequently Asked Questions

Divide the percentage by 100 and multiply by the number. For example, 15% of 200 is 15 ÷ 100 × 200 = 30.
Subtract the old value from the new value, divide by the old value and multiply by 100. A result above zero is an increase and below zero is a decrease.
If a rate moves from 10% to 12%, it rose by 2 percentage points, which is a 20% increase in the rate. The two are often confused in news reports.
The second change applies to a bigger number. 100 up 50% is 150, and 150 down 50% is 75, not 100.

Disclaimer: results are calculated in your browser from the numbers you enter. Check important results before you rely on them for money, health, safety or legal decisions.