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Percentage Calculator

Find what percent one number is of another, take a percentage of a number, or calculate percentage increase and decrease — with the working shown.

Percentage Calculator: with the default inputs, result is 30.

Try an example
Result
30
In words
15% of 200 is 30
15% of 200
  • 15% — 303015%
  • The other 85% — 17017085%
Common percentages of 200
PercentValue
1%2
5%10
10%20
15%30◀ your answer
20%40
25%50
30%60
40%80
50%100
60%120
75%150
90%180
112 of 13

Percentages add and split: 15% is 10% plus half of it, and 45% is 50% minus 5%. That is the whole trick to doing them in your head.

Math verified by automated testsUpdated 2026-09-08

How this is worked out

The formula

X% of Y = X ÷ 100 × Y
X is what % of Y = X ÷ Y × 100
% change = (new − old) ÷ |old| × 100
% difference = |X − Y| ÷ ((|X| + |Y|) ÷ 2) × 100

Open How it’s calculated above to see this worked through with your own numbers.

What you enter

What do you want to find?
Choose one of 5 options.What is X% of Y? · X is what percent of Y? · Percent change from X to Y · X is Y% of what number? · Percentage difference between X and Y
X
A number.defaults to 15
Y
A number.defaults to 200

What you get back

Resultmain answer
In words

About this calculator

"Percent" means "per hundred", so every percentage problem is a ratio with 100 in it somewhere. Pick the question you're asking, type the two numbers, and the calculator shows the answer and each step of the arithmetic.

The five common questions

  • What is 15% of 200? Convert the percent to a decimal (0.15) and multiply: 30.
  • 30 is what percent of 200? Divide and multiply by 100: 15%.
  • Percent change from 200 to 230? Difference over the original: 30 ÷ 200 = 15% increase.
  • 30 is 15% of what? Divide by the decimal: 30 ÷ 0.15 = 200.
  • Percentage difference between 200 and 230? Difference over the average of the two: about 14%. Use this when neither number is the "original".

Percent change vs. percentage points

Going from 10% to 15% is a 5 percentage-point rise but a 50% increase. When you compare two percentages, say which one you mean.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the percent by 100 to get a decimal, then multiply. 25% of 80 is 0.25 × 80 = 20.

How do I work out what percent one number is of another?

Divide the part by the whole and multiply by 100. 20 out of 80 is 20 ÷ 80 × 100 = 25%.

What's the difference between percent change and percent difference?

Percent change measures growth from a starting value, so direction matters. Percent difference compares two values symmetrically using their average, so it's the same whichever you list first.

Can a percentage be more than 100?

Yes. 300 is 150% of 200, and a price that triples has increased 200%.

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