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Percentage Calculator

Find a percentage of a number, work out what percent one value is of another, or calculate percentage increase and decrease. Every answer shows the full working, so you can learn the method for exams — not just copy the result.

%
Answer
100

20% of 500 is 100

Step-by-step solution
  1. 20% of 500 = (20 ÷ 100) × 500
  2. = 0.2 × 500
  3. = 100

How to use the percentage calculator

  1. Choose what you want to calculate — for example "What is X% of Y?" or "Percentage change".
  2. Type the two numbers. The answer updates instantly as you type.
  3. Read the step-by-step working below the answer, or copy the link to share the exact calculation.

Formulas

X% of Y(X ÷ 100) × Y
What % is A of B(A ÷ B) × 100
Percentage change((New − Old) ÷ Old) × 100
Positive = increase, negative = decrease.
Increase Y by X%Y × (1 + X/100)
Decrease Y by X%Y × (1 − X/100)

Solved examples

Example 1: You scored 452 out of 500 in your board exams. What is your percentage?

  • Percentage = (452 ÷ 500) × 100
  • = 0.904 × 100

Answer: 90.4%

Example 2: A phone costing ₹15,000 becomes ₹18,000. By what percent did the price rise?

  • Change = 18,000 − 15,000 = 3,000
  • % change = (3,000 ÷ 15,000) × 100

Answer: 20% increase

Example 3: What is 18% GST on ₹2,450?

  • 18% of 2,450 = (18 ÷ 100) × 2,450

Answer: ₹441

What does "percent" mean?

"Per cent" means "per hundred". Saying 35% is the same as saying 35 out of every 100, or the fraction 35/100, or the decimal 0.35. Because every percentage is out of the same base of 100, percentages make it easy to compare things of different sizes — like marks in two exams with different maximum marks.

To turn any fraction into a percentage, multiply it by 100. To turn a percentage back into a decimal, divide by 100. That single idea is behind every formula on this page.

Percentage shortcuts for competitive exams

Memorise common fraction–percent pairs: 1/2 = 50%, 1/3 = 33.33%, 1/4 = 25%, 1/5 = 20%, 1/6 = 16.67%, 1/8 = 12.5%, 1/9 = 11.11%, 1/10 = 10%. Aptitude questions in SSC, banking and placement tests are built around these values.

Use the multiplier method for successive changes: a 20% rise followed by a 10% fall is 1.20 × 0.90 = 1.08, a net 8% increase — not 10%. And note that X% of Y always equals Y% of X, so 8% of 50 is the same as 50% of 8 = 4.

📘 Learn it in your NCERT syllabus

Free chapter notes, flashcards and quizzes on TalentJR CBSE.

🎯 Asked in competitive exams

This topic regularly appears in the quantitative aptitude section of:

  • SSC CGL & CHSL
  • IBPS & SBI PO / Clerk
  • RRB NTPC
  • Campus placement aptitude tests
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Frequently asked questions

How do I calculate the percentage of marks?

Divide the marks you scored by the total marks and multiply by 100. For example, 452 out of 500 is (452 ÷ 500) × 100 = 90.4%. Select "What % is A of B" in the calculator to do this instantly.

How do I calculate percentage increase?

Subtract the old value from the new value, divide the result by the old value, then multiply by 100. If the answer is negative it is a percentage decrease.

Is a 10% increase followed by a 10% decrease back to the original?

No. 100 increased by 10% is 110; 110 decreased by 10% is 99. The net effect is a 1% decrease, because the second 10% is taken on a larger number.

How do I find the original price before a percentage increase?

Divide the new price by (1 + rate/100). For example, if a price after an 18% increase is ₹1,180, the original price is 1,180 ÷ 1.18 = ₹1,000.

What is the difference between percentage and percentage points?

If an interest rate rises from 5% to 6%, it rose by 1 percentage point, but by 20 percent (because 1 is 20% of 5). News reports and exam questions often test this difference.

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