%Percentage Calculator
Calculate percentages easily - what is X% of Y, percentage increase/decrease, and more
Last updated: November 7, 2025
This percentage calculator simplifies a common question: What percent of X is Y? With just two inputs, we calculate the third value instantly. You can also work backwards to find a percentage of a number or determine percentage changes.
Beyond basic math, this tool applies across daily life, from shopping discounts and tax calculations to tracking fitness progress and analyzing data. Percentages appear everywhere: in finance for interest rates and sales taxes, in health for body composition, and in business for growth metrics.
Keep reading to discover how to find percentages, understand the percentage formula, and explore real-world applications in statistics, finance, and science.
How to use this percentage calculator
Our percentage calculator offers four calculation modes. Choose the section that matches your needs:
What is p% of x?
This section calculates a given percentage of any number:
- Enter the percentage value
- Enter the number you want to find the percentage of
- The result appears immediately
Example: If you scored 85% on a test worth 40 points, your score is 34 points.
x is what percent of y?
This determines what percentage one number represents of another:
- Enter the number whose percentage you want to find
- Enter the total or reference number
- The calculator shows the percentage instantly
Example: If Maria's monthly rent is $1,350 and her budget is $4,500, her rent is 30% of her monthly budget.
You can also reverse this: If Maria wants rent to be no more than 28% of her budget, with $4,500 as her budget, the calculator shows she can afford up to $1,260 in rent.
x is p% of what?
Use this to find the total value when you know a part and its percentage:
- Enter the number you know
- Enter the percentage it represents
- The calculator reveals the total value
Example: 15 is 6% of what number? Enter 15 and 6%, and you'll see the answer is 250.
What is x increased/decreased by p%?
This shows the effect of a percentage increase or decrease on a value:
- Enter the starting value
- Choose increase or decrease
- Enter the percentage change
- The new value displays instantly
Example: A laptop originally costs $650. After a 25% discount, the new price is $487.50.
Works in reverse too: If the sale price is $52 and the discount is 20%, the calculator shows the original price was $65.
What is the percentage? How to find the percentage of something
A percentage is a way to express a dimensionless relationship between two numbers, similar to ratios and fractions. Percentages work well for large numbers (like lottery odds), averages (like course grades), and very small values (like parts per million in air quality measurements).
One percent equals one hundredth (1/100). The percent sign (%) is standard, though "pct" appears occasionally. So 7 percent equals 7%, 7 pct, 0.07, 7/100, or seven-hundredths. This percentage calculator handles decimal fractions and percentages seamlessly.
Percentages help answer: How big is one number relative to another? Imagine a box of 60 donuts. To find 35% of 60, think of 60 divided into 100 equal parts (each part = 0.6 donuts). Then 35 of those parts equals 35% of 60. Let's calculate: 35/100 × 60 = 21. So 35% of 60 donuts is 21 donuts.
Quick tip: To divide by 100, move the decimal point two places left. In 35/100 × 60, you could do (35 × 60)/100 = 2100/100 = 21. Enter 35 and 60 in our calculator, and you'll see "35% of 60 is 21."
How to find the percentage of two numbers: Real-world examples
A percentage expresses the relation between two numbers as a fraction of 100. If number A is 20% of number B, then A to B equals 20 to 100, or 1 to 5, meaning A is five times smaller than B.
Let's explore percentages with a practical example: Imagine a container with 80 compartments arranged in a grid. Each compartment represents 1% of the total. Fill each compartment evenly with marbles.
Starting simple: With 80 marbles total, how many represent 3%?
Each compartment gets one marble, so 1% = 1 marble, and 3% = 3 marbles.
Scaling up: Now with 320 marbles, how many are 12%?
Each compartment gets 4 marbles (320 ÷ 80 = 4). So 12% = 12 compartments × 4 marbles = 48 marbles.
Handling decimals: With 180 marbles, what's 1%?
After distributing evenly, 1% of 180 equals 1.8 marbles. For 14%: 1.8 × 14 = 25.2 marbles.
Why percentages matter: If you score 142 points on a test, that number alone doesn't tell you much. But knowing it's 89% of 160 points makes your performance clear. Percentages standardize comparisons across different scales.
Percentages convert easily to decimals: divide by 100. So 12% = 0.12. In chemistry and physics, percentages often communicate concentrations and efficiencies more clearly than raw decimal fractions.
How to find the percentage of a number: Other examples
While our percentage calculator is fast and accurate, understanding the math helps with mental calculations and builds number sense.
Example 1: In a group of 8 children, 3 are girls. What percentage are girls?
The ratio is 3 out of 8, or 3/8. To find the percentage: (3/8) × 100 = 37.5%. So 37.5% of the group are girls.
Example 2: A fruit basket contains 45% apples out of 40 total fruits. How many apples are there?
Use the formula: part = (percentage/100) × whole
Apples = (45/100) × 40 = 0.45 × 40 = 18 apples
Example 3: You spent $18, which is 36% of your weekly allowance. What was your total allowance?
Use the formula: whole = (part/percentage) × 100
Allowance = ($18/36) × 100 = 0.5 × 100 = $50
How to calculate the percentage: What's the percentage formula?
Percentages involve three components: the percentage value, the whole amount, and the part. Depending on what you're solving, use one of these formulas:
Finding the percentage: percentage = (part/whole) × 100
Answers: "What percentage of 50 is 15?" → (15/50) × 100 = 30%
Finding the part: part = (percentage/100) × whole
Answers: "What is 30% of 50?" → (30/100) × 50 = 15
Finding the whole: whole = (part/percentage) × 100
Answers: "15 is 30% of what?" → (15/30) × 100 = 50
These three formulas cover all percentage calculations. Our calculator applies them automatically based on your selected calculation type.
History of percentage: the percent sign
Ancient Romans used fractions divided by 100 for calculations, similar to modern percentages. After the decimal system spread, computations with a denominator of 100 became standard. Medieval arithmetic texts used this method for financial calculations like interest rates.
The percent sign (%) gained popularity in the 20th century after centuries of evolution. The term "percent" comes from Italian "per cento" (for a hundred), not Latin "per centum" as often believed. Over time, "cento" gradually transformed into two circles separated by a horizontal line, creating the modern % symbol.
In programming, % often represents the modulo operator. In experimental physics, % expresses relative error between true and observed values in measurements.
Related symbols:
- ‰ - per mille (per thousand), used for finer measurements
- ‱ - per myriad (per ten thousand), also called basis points in finance
Higher proportions use parts-per notation, like parts-per-million (PPM), commonly used to measure substance concentrations in solutions or air quality metrics.
What is per mille? What is a basis point?
Per mille (‰) represents one thousandth (1/1000 or 0.001), similar to percent but 10 times smaller. If a monthly budget is $3,200 and you allocate 2 per mille to a specific expense, you'd spend $6.40 (2 × $3.20).
Per myriad or basis point (‱) equals one ten-thousandth (1/10,000 or 0.0001). It's 10 times smaller than per mille. To convert basis points to percents, divide by 100. So 250 basis points = 2.5%.
Finance professionals use basis points to discuss interest rate changes. A 0.25% rate increase equals 25 basis points, providing clearer precision in financial communication.
Percentage points (percent points)
Percentage points measure the absolute difference between two percentages, not the relative change. This distinction matters when comparing percentage values.
Example: A candidate's approval rating was 15% last month. After recent events, it's now 18%. The change is 3 percentage points (18% - 15% = 3 pp), not 3%. The relative change is actually (3/15) × 100 = 20% increase.
Key differences:
- Change in percentage points: The absolute difference (e.g., from 15% to 18% = 3 pp)
- Change in percentage: The relative change (e.g., 3 pp increase from 15% = 20% relative increase)
Understanding this distinction helps avoid confusion when analyzing polls, statistics, or financial reports where percentage changes are discussed.
Applications of percentages in daily life
Percentages appear throughout daily life, making them essential for practical decision-making:
Shopping and Discounts
Calculate sale prices, compare discounts, and determine final costs after tax. A $120 item with a 35% discount costs $78 before tax.
Finance and Banking
Calculate interest rates, loan payments, investment returns, and tax amounts. A 4.5% annual interest rate on $10,000 earns $450 per year.
Health and Fitness
Track body fat percentage, calculate calorie deficits, and monitor progress. Losing 8% of body weight might mean dropping from 180 lbs to 165.6 lbs.
Education and Grading
Calculate test scores, determine final grades, and analyze performance. Scoring 42 out of 50 questions equals 84%.
Business and Statistics
Analyze growth rates, market share, profit margins, and survey results. A company growing from $500K to $650K revenue represents a 30% increase.
Frequently Asked Questions
A percentage is a dimensionless ratio of two numbers expressed as a fraction of 100. It can be used to compare two numbers and find out how much one is more than the other or compare numbers against a common scale. For example, 25% means 25 out of 100, or one quarter.
To calculate x percent of y: Divide x by 100, then multiply the result by y. For example, to find 30% of 150: (30/100) × 150 = 0.30 × 150 = 45. So 30% of 150 is 45.
To find what percentage x is of y: Divide x by y, then multiply by 100. For example, to find what percent 45 is of 150: (45/150) × 100 = 0.30 × 100 = 30%. So 45 is 30% of 150.
60% of 1260 equals 756. To calculate: Divide 60 by 100 (60/100 = 0.6), then multiply by 1260 (0.6 × 1260 = 756). So 60% of 1260 is 756.
Percentage points measure the absolute difference between two percentages, while percentage change measures the relative change. For example, if something increases from 10% to 15%, that's a 5 percentage point increase, but a 50% relative increase ((5/10) × 100 = 50%).
To calculate percentage increase: Subtract the original value from the new value, divide by the original value, then multiply by 100. Formula: ((New Value - Old Value) / Old Value) × 100. For example, if a price increases from $50 to $65: ((65-50)/50) × 100 = 30% increase.
To calculate percentage decrease: Subtract the new value from the original value, divide by the original value, then multiply by 100. Formula: ((Old Value - New Value) / Old Value) × 100. For example, if a price decreases from $100 to $75: ((100-75)/100) × 100 = 25% decrease.
Per mille (‰) represents one thousandth (1/1000 or 0.001), which is 10 times smaller than a percent. It's used for finer measurements. For example, 5‰ means 5 out of 1000, or 0.5%.
A basis point (‱) equals one ten-thousandth (1/10,000 or 0.0001), which is 100 times smaller than a percent. It's commonly used in finance to discuss interest rate changes. For example, 250 basis points equals 2.5%.