How to Calculate Percentage of a Number (with Money Examples)

A percentage is just a fraction of 100 — the word literally means "per hundred." This guide covers the everyday, money-related percentage problems you meet while shopping, saving and budgeting. (If you're a student working out exam scores, see our separate guide on calculating percentage of marks instead.)

What is X% of a number?

Multiply the number by the percentage divided by 100: X% of Y = (X ÷ 100) × Y. Example: 18% GST on a ₹2,000 bill = 0.18 × 2,000 = ₹360, so the total is ₹2,360.

Percentage increase and decrease

Use ((new − old) ÷ old) × 100. If your salary rises from ₹40,000 to ₹46,000, that's (6,000 ÷ 40,000) × 100 = 15% increase. A price falling from ₹250 to ₹200 is a 20% decrease.

Reverse percentage (finding the original)

Sale prices often show the discounted amount. To find the original, divide by (1 − discount). A jacket costing ₹1,200 after 20% off was ₹1,200 ÷ 0.80 = ₹1,500 originally.

Percentage vs percentage points

These aren't the same. If an interest rate goes from 8% to 10%, that's a rise of 2 percentage points — but a 25% increase in the rate itself. Mixing them up is a common money mistake.

Everyday money uses

• Shopping discounts — the Discount Calculator shows your final price and savings.
• Restaurant tips — split the bill with the Tip Calculator.
• GST — add or remove tax with the GST Calculator.
• Savings growth — see compounding with the Compound Interest Calculator.

Skip the maths

Our Percentage Calculator solves all of these — "what is X% of Y", "X is what % of Y" and percentage change — instantly and free.