Percentage Calculator

Choose what you want to work out, enter two numbers and the answer appears with the working. It handles scores, prices, VAT, discounts and percentage change.

Percentage formulas

• Percentage of a number: X% of Y = X ÷ 100 × Y
• What percent X is of Y: X ÷ Y × 100
• Percentage change: (new − old) ÷ old × 100
• Adding a percentage: amount × (1 + X ÷ 100)
• Taking off a percentage: amount × (1 − X ÷ 100)

Worked examples

Your score as a percentage

You scored 54 out of 75 in a test. Your percentage is 54 ÷ 75 × 100 = 72%. The same method turns any mark into a percentage, which is how most schools compare results from tests with different totals.

Percentage of money

A trader gives a 10% discount on a ₦45,000 phone. The discount is 10 ÷ 100 × 45,000 = ₦4,500, so the customer pays ₦40,500. To check, 45,000 × 0.9 gives the same answer in one step.

VAT in Nigeria

Value Added Tax in Nigeria is 7.5%. A ₦20,000 invoice plus VAT is 20,000 × 1.075 = ₦21,500. To remove VAT from a price that already includes it, divide by 1.075 instead: ₦21,500 ÷ 1.075 = ₦20,000.

Percentage increase

A bag of rice rose from ₦60,000 to ₦75,000. The increase is 15,000, and 15,000 ÷ 60,000 × 100 = 25%. Always divide by the old value, not the new one, or the answer comes out too small.

Common mistakes

• Dividing by the new value when working out a percentage change.
• Adding percentages one after another: two 10% rises make 21%, not 20%, because the second rise is on a bigger number.
• Removing VAT by subtracting 7.5% of the final price. Divide by 1.075 instead.

Frequently Asked Questions

For school results, try the CGPA Calculator or the CGPA to Percentage Converter.