Calculator

Percentage Calculator – % of, Change, Increase

Find a percentage of a number, what percent one number is of another, a percentage change, or a value after an increase or decrease.

Percentage (%)

Of this number

Direction

About the Percentage Calculator

The Percentage Calculator answers the five questions people ask about percentages: what is X% of Y, X is what percent of Y, the percentage change from one number to another, a number after a percentage increase or decrease, and the original number before a percentage change. It shows the working so you can check it.

Percentage Calculator quick facts

Modes:

Five: X% of Y, X is what % of Y, percentage change, after an increase or decrease, and find the original

Example:

20% of 500 is 100

Percentage change:

(new − old) ÷ old × 100. From 80 to 100 is +25%

Working:

The steps are shown so you can check them

How to use the Percentage Calculator

Choose what you want to find: X% of Y, X is what % of Y, % change, increase or decrease, or find the original.
Enter the two numbers (and the direction for increase or decrease).
Read the answer and the formula used.

The five percentage questions

Almost every percentage problem is one of five: a percentage of a number, one number as a percentage of another, the change between two numbers, a number after an increase or decrease, or the original before a change. Pick the mode that matches your question and the calculator uses the right formula.

Worked examples

20% of 500 is 100. 25 is 12.5% of 200. A price that moves from ₹80 to ₹100 has risen 25%. ₹1,000 plus 18% is ₹1,180, and ₹1,180 including 18% was ₹1,000 before.

Common mistakes

Adding a discount percentage back to undo it, dividing by the wrong number when finding a percentage, calculating percentage change from zero (it is undefined), and mixing up percent with percentage points.

Frequently asked questions about the Percentage Calculator

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 20% of 500 is 500 × 20 ÷ 100 = 100. The calculator does this for you and shows the working, which is useful for discounts, tips, marks and tax.

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

Divide the part by the whole and multiply by 100. For example, 25 out of 200 is 25 ÷ 200 × 100 = 12.5%. Use the "what percent" mode to get this directly, which is handy for marks, completion rates and shares.

How do I calculate percentage change?

Subtract the old value from the new value, divide by the old value and multiply by 100. For example, going from 80 to 100 is (100 − 80) ÷ 80 × 100 = +25%. A negative result means a decrease, such as a price drop.

Why does a 20% discount followed by a 20% increase not return the original price?

Because the two percentages apply to different amounts. A price of 100 cut by 20% is 80, and 20% of 80 is only 16, giving 96. To get back to 100 you need a 25% increase.

How do I remove a percentage that was added, such as GST?

Divide the final amount by 1 plus the percentage as a decimal. For example, ₹1,180 including 18% is 1,180 ÷ 1.18 = ₹1,000. Use the "Find the original" mode, which does this reverse calculation for any percentage.

What is the difference between a percentage and a percentage point?

A rise from 4% to 5% is one percentage point but a 25% increase in the rate itself. This calculator reports percent change, not percentage points.

Free, no sign-up. Reviewed 15 October 2026 by the Gopafy team. See all free tools.