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Percentage Calculator

Work out any everyday percentage: X% of a number, what percent one number is of another, the percentage increase or decrease from one value to another, and the percentage difference between two values.

How to use this calculator

  1. Choose the question: X% of Y, X is what % of Y, % change or % difference.
  2. Enter the two numbers. The labels change to show which number goes where.
  3. Read the answer and the sentence under it, which states the result in plain words. Use Share to copy or send it.

Formula

X% of Y = X × Y ÷ 100 · X is (X ÷ Y × 100)% of Y · Change = (New − Old) ÷ Old × 100 · Difference = |A − B| ÷ ((A + B) ÷ 2) × 100

X, Y
the two values you enter
Old, New
the before and after values in a percentage change
A, B
the two values compared in a percentage difference; their order does not matter

Percentage change is negative when the value falls. Percentage difference is never negative.

Worked example

A salary rises from ₹50,000 to ₹57,500 a month.

  1. Difference57,500 − 50,000 = 7,500
  2. Divide by original7,500 ÷ 50,000 = 0.15
  3. Convert to percent0.15 × 100

That is a 15% increase.

How to find X% of a number

Multiply the number by the percentage and divide by 100. For 5% of 57,500: 57,500 × 5 ÷ 100 = 2,875. Choose X% of Y above and enter 5 and 57,500 to get the same answer.

  • 5% of 57,500 = 2,875
  • 20% of 57,500 = 11,500
  • 15% of 1,250 = 187.5
  • 12.5% of 800 = 100
  • 18% of 2,499 = 449.82, the GST on a ₹2,499 item. To add or remove GST in one step, use the GST calculator.

Working out a percentage in your head

Start from 10%, which is the number with the decimal point moved one place to the left, and scale from there. 10% of 57,500 is 5,750, so 5% is half of that, 2,875, and 20% is double, 11,500. For 1%, move the decimal point two places: 1% of 57,500 is 575.

How to work out what percent one number is of another

Divide the part by the whole and multiply by 100. Scoring 437 out of 500 is 437 ÷ 500 × 100 = 87.4%. Attending 45 of 60 classes is 75%; the attendance calculator goes further and tells you how many classes you can still miss.

Percentage increase and decrease

Subtract the old value from the new one, divide by the old value and multiply by 100. A positive answer is an increase and a negative answer is a decrease. Choose % change above, and enter the old value first.

  • A price rising from ₹1,200 to ₹1,500: (1,500 − 1,200) ÷ 1,200 × 100 = 25% increase.
  • A bill falling from ₹8,000 to ₹6,000: (6,000 − 8,000) ÷ 8,000 × 100 = 25% decrease.

Percentage change or percentage difference?

Use percentage change when there is a clear before and after, such as last year's and this year's price. The answer depends on which value came first.

Use percentage difference when neither value is the starting point, such as the prices of the same phone in two shops. It divides the gap by the average of the two values, so the answer is the same whichever you enter first. For 40 and 60, the change from 40 to 60 is +50% and from 60 to 40 is −33.33%, but the percentage difference is 40% either way: 20 ÷ 50 × 100.

Percentage points are not percentages

If an interest rate moves from 4% to 5%, that is a rise of one percentage point, but a 25% increase in the rate itself. Both statements are correct and they mean very different things. News reports about rates, vote shares and unemployment usually mean percentage points.

Why a rise and a fall of the same percentage do not cancel out

A 20% fall followed by a 20% rise does not return to the starting value. ₹100 falls to ₹80, and 20% of ₹80 is only ₹16, so you end at ₹96. The second percentage applies to a smaller base. Recovering a 20% fall actually needs a 25% rise.

The same effect is why two discounts in a row add up to less than their sum. The discount calculator works out stacked offers such as 50% plus an extra 20%.

Things to keep in mind

  • Percentage change needs a non-zero starting value. Growth from zero cannot be expressed as a percentage.
  • Results are shown to four decimal places where needed; round to the precision your situation requires.

Frequently asked questions

How do I calculate percentage of marks?

Choose X is what % of Y and enter the marks you scored and the total marks. If you scored 437 out of 500, that is 437 ÷ 500 × 100 = 87.4%. If your result is a CGPA instead, convert it with the CGPA calculator.

How do I calculate percentage increase?

Subtract the old value from the new value, divide by the old value and multiply by 100. From ₹1,200 to ₹1,500 is (300 ÷ 1,200) × 100 = 25%. Choose % change above and enter the old value first.

What is the difference between percentage change and percentage difference?

Percentage change measures how much a value moved from a starting point, so the order matters and the result can be negative. Percentage difference compares two values with no starting point, using their average, so the order does not matter. For 40 and 60, the change is +50% or −33.33% depending on direction; the difference is 40%.

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

Divide the new value by (1 + rate ÷ 100). A price of ₹1,180 after an 18% increase came from ₹1,180 ÷ 1.18 = ₹1,000. The GST calculator does exactly this for tax.

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