Calculate percentages instantly — find percentage of any number, percentage change, and what percent one value is of another.
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Percentage Calculator
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What is X% of Y?
Result
X is what percent of Y?
Percentage
Percentage change from X to Y
Percentage Change
What is a Percentage Calculator?
A percentage calculator is a mathematical tool that helps you perform various percentage-related calculations quickly and accurately. Percentages are used everywhere in daily life — from calculating tips at restaurants and discounts while shopping to understanding statistics, financial reports, and academic grades. Our free online percentage calculator eliminates manual calculations, reducing errors and saving time.
The word "percentage" comes from Latin "per centum," meaning "by the hundred." When we express a number as a percentage, we describe it as a fraction of 100. For example, 25% means 25 out of 100, or one-quarter of a whole.
How to Calculate Percentages
Finding X% of a Number
To find what percentage of a number equals, multiply the number by the percentage and divide by 100:
Result = (Percentage × Number) ÷ 100
Example: What is 25% of 200?
Result = (25 × 200) ÷ 100 = 5,000 ÷ 100 = 50
Finding What Percent X is of Y
Percentage = (Part ÷ Whole) × 100
Example: 45 is what percent of 180?
Percentage = (45 ÷ 180) × 100 = 0.25 × 100 = 25%
Calculating Percentage Change
Change = ((New - Original) ÷ Original) × 100
Example: Price increased from $80 to $100. What's the increase?
Shopping: Calculate discounts (20% off $50 = $10 savings)
Tipping: Figure out 15-20% tips at restaurants
Grades: Convert scores to percentages (85 out of 100 = 85%)
Finance: Calculate interest rates and investment returns
Statistics: Understand survey results and data analysis
Health: Track weight loss percentages or fitness goals
Frequently Asked Questions
For quick mental math, break percentages into easier parts. To find 15%, calculate 10% (move decimal left) and add half of that (5%). For example, 15% of 80: 10% = 8, 5% = 4, so 15% = 12.
Yes! Percentages over 100% represent values greater than the original. If sales increased from 100 to 250, that's a 150% increase.
Divide the numerator by denominator, then multiply by 100. For example, 3/4 = 0.75 × 100 = 75%.
Percentage represents a portion of 100. Percentile shows ranking in a distribution — if you're in the 80th percentile, you scored higher than 80% of people.
A percentage expresses a number as a portion of one hundred. The word comes from the Latin per centum, meaning "by the hundred". Percentages exist because comparing fractions with different denominators is awkward, while comparing everything against a common base of 100 is straightforward. A percentage calculator handles the three core operations: finding a percentage of a number, finding what percentage one number is of another, and calculating percentage change.
How to Use This Percentage Calculator
Pick the calculation you need.Percentage of a number, one number as a percentage of another, or percentage increase and decrease.
Enter your two values.Type the figures into the relevant fields.
Read the result.The answer appears immediately, along with the working where relevant.
The Three Core Formulas
Percentage of a number: Result = Number x (Percent / 100)
15% of 240 = 240 x 0.15 = 36
X as a percentage of Y: Result = (X / Y) x 100
37 out of 50 = (37 / 50) x 100 = 74%
Percentage change: Result = ((New - Old) / Old) x 100
From 50 to 65 = ((65 - 50) / 50) x 100 = 30%
Worked Example: Percentage Change
A monthly bill rose from 84 to 105
Step 1: Find the difference
105 - 84 = 21
Step 2: Divide by the original value
21 / 84 = 0.25
Step 3: Convert to a percentage
0.25 x 100 = 25%
The bill increased by 25 percent
Always divide by the original
Dividing by the new value instead of the old one is the most frequent percentage error. Using 105 as the base gives 20 percent rather than the correct 25 percent. The original value is always the reference point for change.
The Asymmetry of Rises and Falls
An equal percentage down and up does not return you to the starting point, because the second percentage applies to a smaller base. This is not a quirk; it has real consequences in investing.
Loss
Value from 100
Gain Needed to Recover
10%
90
11.1%
20%
80
25%
33%
67
50%
50%
50
100%
75%
25
300%
A portfolio that halves needs to double simply to get back to even. This is why avoiding large losses matters more to long-term returns than capturing large gains, a point that gets lost when performance is quoted as an average.
Percentage Points Versus Percent
These are routinely confused in news reporting, and the difference is substantial.
An interest rate moves from 4% to 6%
Change in percentage points: 6 - 4 = 2 percentage points
Percentage change in the rate: ((6 - 4) / 4) x 100 = 50%
Both are true: a rise of 2 percentage points, which is a 50 percent increase in the rate
Why the distinction matters
Saying a rate "rose 50 percent" sounds alarming; saying it "rose two points" sounds modest. Both describe the identical change. When reading about interest rates, poll results or unemployment figures, check which measure is being used, because the choice is often rhetorical.
Mental Shortcuts Worth Knowing
10 percent: move the decimal one place left. 10 percent of 340 is 34.
1 percent: move it two places. 1 percent of 340 is 3.40.
5 percent: take 10 percent and halve it.
15 percent: 10 percent plus half of it again. Useful for tipping.
20 percent: 10 percent doubled.
The reversal trick: x percent of y equals y percent of x. Finding 4 percent of 75 is awkward; 75 percent of 4 is obviously 3.
The reversal trick in practice
Because multiplication is commutative, 18 percent of 50 is the same as 50 percent of 18, which is simply 9. Whenever one of the two numbers is easier to work with, swap them. It is exact, not an approximation, and it turns many awkward mental calculations into trivial ones.
Where Percentages Appear Daily
Context
What Is Calculated
Shopping
Discounts, sales tax, VAT
Dining
Tips and service charges
Borrowing
Interest rates, APR
Investing
Returns, portfolio allocation
Education
Test scores, grade weighting
Business
Margins, commission, growth rates
People Also Ask
Convert the percentage to a decimal by dividing by 100, then multiply. To find 15 percent of 240, multiply 240 by 0.15, giving 36. This single operation covers tips, taxes, discounts and commission.
Subtract the old value from the new value, divide by the old value, then multiply by 100. Going from 50 to 65 is an increase of 15, and 15 divided by 50 is 0.30, so a 30 percent rise. Always divide by the original figure, never the new one.
Because each percentage applies to a different base. A price of 100 falling 20 percent becomes 80. A 20 percent rise on 80 is only 16, giving 96 rather than 100. Recovering a 20 percent fall requires a 25 percent rise. This asymmetry is why investment losses are harder to recover than they appear.
If an interest rate moves from 4 percent to 6 percent, that is a rise of two percentage points but a 50 percent increase in the rate itself. Both statements are correct and they describe very different magnitudes, which is why the distinction matters in reporting on rates, polls and statistics.
Divide the part by the whole and multiply by 100. If 37 out of 50 questions were correct, divide 37 by 50 to get 0.74, which is 74 percent. The number you are comparing against always goes on the bottom.
Khan Academy — Free lessons on percentage calculation and applications.
This calculator is provided for educational purposes. For financial, tax or academic decisions, verify results independently and consult a qualified professional where appropriate.