Percentage Calculator

Every everyday percentage question in one place — what is X% of Y, X is what percent of Y, percent increase or decrease, and more. Type your numbers and read the answer as a full sentence.

5 calculators, live Plain-English answers 100% client-side · free · no signup

What is a percent of a number?

What is % of ?
30 15% of 200 is 30.

X is what percent of Y?

is what percent of ?
25% 45 is 25% of 180.

Percent increase or decrease

From to ?
+25% From 80 to 100 is a 25% increase.

Increase or decrease a number by a percent

%
230 200 increased by 15% is 230.

X is P% of what number?

is % of what?
200 30 is 15% of 200.

A percentage is one line of math — running your whole operation is the work.

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How to calculate a percentage

A percentage is just a fraction out of 100 — the word literally means "per hundred". Every everyday percentage question is one of a few small formulas, and the five calculators above cover the ones people actually search for. Type your own numbers into any of them and the answer updates instantly, written out as a full sentence you can copy.

The formulas, in plain terms

QuestionFormulaExample
What is P% of N?N × P / 10015% of 200 = 30
X is what percent of N?X / N × 10045 of 180 = 25%
Percent change A → B(B − A) / A × 10080 → 100 = +25%
N changed by P%N × (1 ± P/100)200 +15% = 230
X is P% of what?X / (P / 100)30 is 15% of 200

Percent of a number

To find a percent of a number, turn the percent into a decimal (divide by 100) and multiply. A 15% tip on a $200 bill is 200 × 0.15 = $30. The same move handles discounts, tax, commission and interest for a single period.

What percent one number is of another

To find what percent a part is of a whole, divide the part by the whole and multiply by 100. If 45 of 180 seats are taken, that is 45 / 180 × 100 = 25% full. This is the calculation behind test scores, conversion rates and "how much is left".

Percent increase and decrease

Percent change compares a new value to an old one: subtract the old from the new, divide by the old, and multiply by 100. Going from 80 to 100 is a 25% increase; going from 100 to 80 is a 20% decrease — the two are not the same, because the starting point (the denominator) changed. A positive answer is an increase, a negative answer is a decrease.

Is my data private?

Yes. Every calculation runs as plain JavaScript inside your browser — no server call, no upload, nothing logged or stored. Whatever you enter never leaves your device. Refresh the page and it is gone.

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