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Percentage Calculator

Updated · By the CalculatorDash editorial team · How we check our maths

Quick answer

To find X% of Y, multiply Y by X ÷ 100: 15% of 240 is 36. To find what percent A is of B, divide A by B and multiply by 100. Percentage change is (new − old) ÷ old × 100, so going from 240 to 300 is a 25% increase.

Percentages

X% of Y

36

X is what % of Y
6.25%
% change from X to Y
1,500%
Y increased by X%
276
Y decreased by X%
204

How this calculator works

Percent means 'per hundred', so every percentage problem is a multiplication or division by 100 in disguise. This calculator answers the five questions people ask most, all from the same two numbers, so you don't need to remember which formula applies.

Be careful with percentage change: it is always measured against the starting value. A rise from 50 to 100 is +100%, but a fall from 100 back to 50 is only −50%. Percentage points are different again: going from a 4% to a 5% interest rate is a rise of one percentage point, or 25%.

The formula

X% of Y
Y × X ÷ 100
X as a % of Y
X ÷ Y × 100
% change
(Y − X) ÷ |X| × 100
Increase / decrease by X%
Y × (1 ± X ÷ 100)

Worked example

With X = 15 and Y = 240: 15% of 240 is 36. 15 is 6.25% of 240. Going from 15 to 240 is a 1,500% increase. 240 increased by 15% is 276, and decreased by 15% is 204.

Tips

  1. 01To add a percentage, multiply by 1 plus the rate: +8% is × 1.08.
  2. 02To reverse a percentage increase, divide, don't subtract: a price that rose 20% to 120 was 100, not 96.
  3. 03Percentages are reversible: 8% of 50 is the same as 50% of 8.

Frequently asked questions

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. 20% of 85 is 85 × 20 ÷ 100 = 17.

How do I calculate percentage increase?

Subtract the old value from the new value, divide by the old value and multiply by 100.

What is the difference between percent and percentage points?

Percentage points measure the gap between two percentages (4% to 5% is 1 point). Percent change measures it relative to the start (a 25% increase).

How do I find the original price before a discount?

Divide the sale price by (1 − discount). A $60 item after 25% off was $60 ÷ 0.75 = $80.