Discount
$80 with a 25% discount.
80 × 0.75 = 60Sale price: $60.Percent Calculator: Make Percentages Easy
Percentages don't have to be complicated. Choose what you want to calculate, enter your numbers, and get the result right away.
Calculate percentages, percentage change, increases and decreases, with clear examples and formulas when you need them.
Choose a calculation type and enter the required values.
Result
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Percentages made simple
Percent means “per hundred.” A percentage shows how large a share is compared to 100 equal parts.
For example, 25% means 25 out of 100 – or one quarter. So 25% of 200 is 50.
Percentage problems usually involve three things: the whole (base value), the percentage rate, and the resulting amount. Once you know any two of them, you can calculate the third.
Below, each of these questions gets its own worked example and formula.
What is X% of Y?
What is 20% of 150?
Here, the whole and the percentage rate are known, and the percentage amount – the actual share – is what you're solving for.
150 × 20 / 100 = 30
20% of 150 is 30.
Part = Whole × Percentage / 100
X is what percent of Y?
30 is what percent of 150?
Here, the part and the whole are known, and the percentage rate is what you're solving for.
30 / 150 × 100 = 20%
30 is 20% of 150.
Percentage = Part / Whole × 100
30 is 20% of what number?
This direction is easy to miss because the question rarely states “of what” outright. The part and the percentage rate are known, and the whole is what's missing.
30 × 100 / 20 = 150
30 is 20% of 150.
Whole = Part × 100 / Percentage
How do you calculate percentage change?
Old value: 100 · New value: 125
Percentage change measures how much a value has changed compared to a known starting value. That starting value is always the reference point.
(125 - 100) / 100 × 100 = 25%
The value increased by 25%.
(new value - old value) / old value × 100
100 → 80 = -20%
A negative result means the value decreased.
How do you increase a number by a percentage?
Increase $100 by 20%
The fastest way is a multiplier: 1 plus the percentage divided by 100. That skips the detour through the percentage-change formula.
100 × 1.20 = 120
$100 increased by 20% is $120.
Original value × (1 + percentage / 100)
How do you decrease a number by a percentage?
Decrease $100 by 20%
The same trick works for a decrease, using 1 minus the percentage divided by 100 instead.
100 × 0.80 = 80
$100 decreased by 20% is $80.
Original value × (1 - percentage / 100)
Percentage formulas at a glance
These six formulas cover every common percentage problem.
Part
Whole × Percentage / 100Percentage
Part / Whole × 100Whole
Part × 100 / PercentagePercentage change
(New - Original) / Original × 100Increase
Original × (1 + Percentage / 100)Decrease
Original × (1 - Percentage / 100)- Whole
- The complete starting amount.
- Part
- The portion of the whole.
- Percentage
- The portion expressed per hundred.
Everyday percentage examples
Price increase
$50 increased by 10%.
50 × 1.10 = 55New price: $55.Pay raise
$3,000 increased by 5%.
3,000 × 1.05 = 3,150New salary: $3,150.Growth
200 to 250.
(250 - 200) / 200 × 100 = 25%Growth: +25%.Decline
100 to 80.
(80 - 100) / 100 × 100 = -20%Decline: -20%.Test score
42 out of 50.
42 / 50 × 100 = 84%Score: 84%.Common percentage mistakes
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“20% of 100” isn't “increase 100 by 20%”
20% of 100 is 20. Increasing 100 by 20% instead gives 120. Both calculations answer different questions, even though the numbers sound similar.
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An increase and decrease don't cancel out
$100 increased by 20% is $120. Decrease that $120 by 20% and you get only $96 – not back to $100 – because the reference value changed between the two steps.
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The original value is always the reference
Percentage change always divides by the old value, never the new one. Only that way does the result describe the actual change from the starting point.
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Percent is not the same as percentage points
If a rate rises from 20% to 25%, that's 5 percentage points, but a relative increase of 25%. Both figures are correct, they just mean different things.
Percent vs. percentage points
A rate rises from 20% to 25%.
Percentage points describe the absolute difference between two percentages. Percent describes the relative change compared to the original percentage – both are correct, but they are not the same thing.
Difference: 5 percentage points · Relative increase: 25%
Both statements are correct, but they describe different aspects of the same change.
Frequently asked questions
What is a percentage?
A percentage describes a part per hundred. For example, 25% means 25 out of 100, or one quarter.
How do you calculate a percentage?
To find a percentage of a number, multiply the whole by the percentage and divide by 100.
How do you calculate what percent one number is of another?
Divide the part by the non-zero whole and multiply the result by 100.
How do you calculate percentage change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. The old value must not be zero.
What is the difference between percent and percentage points?
Percent describes a relative amount. Percentage points describe the direct difference between two percentages, such as 5 points between 20% and 25%.