Need a quick answer? Enter your numbers in the calculator above to find a percentage instantly. Whether you want to know what percent one number is of another, find a percent of a value, or calculate percentage change, this free percentage calculator handles it all.
A percentage is a way to express a number as a fraction of 100. The word itself comes from the Latin "per centum," meaning "by the hundred." When you see 25%, that simply means 25 out of 100.
Percentages show up everywhere. Discounts, tax rates, interest rates, test scores, nutrition labels, and tipping all involve percentage calculations. This tool lets you compute any of them in seconds.
How to Calculate Percentages With This Percent Calculator
This online percentage calculator supports several common calculation types:
- What is P percent of X? Enter the percent and the number. The calculator multiplies them for you.
- X is what percent of Y? Enter both values. The calculator divides and converts to a percentage.
- Percentage change. Enter a starting value and an ending value. The tool returns the percent increase or decrease.
To use it:
- Pick the type of calculation you need.
- Enter your numbers into the fields.
- Read the result instantly.
No sign-up required. No ads blocking your answer. Just enter values and get a result.
The Percentage Formula
The core percentage formula is straightforward:
Percentage = (Part / Whole) × 100
You divide the part by the whole, then multiply the result by 100 to get the percentage. That's it. Every percentage calculation is a variation of this equation.
For example, say 18 out of 60 students passed a quiz. Divide 18 by 60 to get 0.3. Multiply by 100 to get 30%. So 30% of students passed.
How to Find the Percentage of a Number
"What is 15% of 200?" is one of the most common percentage problems. Here is the formula:
Result = (Percentage / 100) × Number
- Convert the percentage to a decimal by dividing by 100. So 15% becomes 0.15.
- Multiply by the number. 0.15 × 200 = 30.
Another example: a food label says one serving contains 12 mg of a nutrient, and the total recommended daily allowance (RDA) is 60 mg. What percentage of the RDA does one serving provide?
(12 / 60) × 100 = 20%. One serving covers 20% of your daily target.
How to Calculate Percent of X
This phrasing flips the question slightly. "How much is 10% off a price of $150?" still uses the same formula.
- Convert: 10% = 0.10
- Multiply: 0.10 × 150 = 15
- Subtract the discount: 150 − 15 = $135
You can also calculate percent of x when the question is "Y is P percent of what?" Rearrange the formula:
X = Y / (P / 100)
If 30 is 25% of some number, then X = 30 / 0.25 = 120.
Percentage, Fraction, and Decimal
Percentages, fractions, and decimals are three ways to express a part of a whole. Converting between them is simple.
| Form | Example |
|---|---|
| Percentage | 75% |
| Decimal | 0.75 |
| Fraction | 3/4 |
Percentage to decimal: Divide by 100. 75% becomes 0.75.
Decimal to percentage: Multiply by 100. 0.45 becomes 45%.
Fraction to percentage: Divide the numerator by the denominator, then multiply by 100. 3/8 = 0.375 × 100 = 37.5%.
These conversions matter when you need to plug values into formulas or compare two numbers expressed in different formats.
The Percent Sign and Per Cent
The percent sign (%) is a shorthand symbol meaning "per hundred." Writing 50% is the same as writing 50 out of 100, or 50/100, or 0.50.
Percent or per cent? Both are correct. "Percent" (one word) is standard in American English. "Per cent" (two words) is common in British English. The meaning is identical.
You may have also seen the per mille symbol (‰), which means "per thousand." It works the same way but uses 1,000 as the base instead of 100. It appears in some financial and scientific contexts but is far less common in everyday use.
Percentage Change and Percent Change
Percentage change measures the increase or decrease between two values. Use it to track price changes, population growth, revenue shifts, or any change between two numbers.
Percentage change = ((New Value − Old Value) / Old Value) × 100
Example: A product cost $80 last month and $92 this month.
- Difference: 92 − 80 = 12
- Divide by the original: 12 / 80 = 0.15
- Multiply by 100: 15%
That's a 15% percentage increase.
If the new value is smaller than the old value, the result is negative. That indicates a percentage decrease. A drop from $80 to $68 is a −15% change.
Percentage Points vs Percentage Change
These two terms sound similar but mean different things. Confusing them leads to real misunderstandings, especially in news and finance.
Percentage points describe the arithmetic difference between two percentages. If an interest rate moves from 4% to 6%, that is a 2 percentage point increase.
Percentage change describes the relative size of that shift. Going from 4% to 6% is a 50% increase (because 2/4 × 100 = 50%).
Both statements are factually correct. They just measure different things. When you read that unemployment "rose 3 percentage points," that is not the same as "rose 3%."
Percentage Difference Calculator
Percentage difference compares two values when neither is clearly the "starting" or "reference" number. It answers: how far apart are these two numbers, relative to their average?
Percentage difference = (|Value 1 − Value 2| / ((Value 1 + Value 2) / 2)) × 100
Example: Compare two test scores, 72 and 88.
- Difference: |72 − 88| = 16
- Average: (72 + 88) / 2 = 80
- Divide: 16 / 80 = 0.20
- Multiply by 100: 20%
The percentage difference between the two scores is 20%. Use this when you want to compare two values without designating one as the baseline.
Percent Error
Percent error measures how far an experimental or estimated value is from a known or accepted value. It is common in science, engineering, and quality control.
Percent error = (|Measured Value − Actual Value| / Actual Value) × 100
Example: You estimate the length of a table at 152 cm. The actual measurement is 150 cm.
- Difference: |152 − 150| = 2
- Divide by actual: 2 / 150 = 0.0133
- Multiply by 100: 1.33%
Your estimate had a 1.33% error. A lower percent error means a more accurate measurement or estimate.
How to Subtract a Percentage
Subtracting a percentage is how you calculate discounts, markdowns, and reductions. There are two quick methods.
Method 1 (two steps):
- Find the percentage of the number. 20% of $250 = $50.
- Subtract it from the original. $250 − $50 = $200.
Method 2 (one step):
Subtract the percent from 100%, then multiply. If you want to remove 20%, multiply by 80% (which is 0.80).
$250 × 0.80 = $200.
Method 2 is faster, especially when you chain multiple calculations. Both give the same result.
To add a percentage (for tax or a tip, for example), just reverse the process. Add the percentage to 100% and multiply. A 15% tip on $60: $60 × 1.15 = $69.
Common Percentage Problems
Here are a few real-world percentage problems and how to solve them.
How much is 20% of 70? 0.20 × 70 = 14.
What percent of 40 is 8? (8 / 40) × 100 = 20%.
A store marks a $120 jacket down by 35%. What is the sale price? $120 × 0.65 = $78.
You scored 42 out of 50 on a test. What is your percentage? (42 / 50) × 100 = 84%.
How do you calculate profit percentage? Profit percentage = ((Revenue − Cost) / Cost) × 100. If you spent $200 and earned $260, your profit percentage is (60 / 200) × 100 = 30%.
How do you calculate an average percentage? Add the percentages together and divide by the count. If three classes scored 80%, 90%, and 85%, the average is (80 + 90 + 85) / 3 = 85%. Note: this works when each group is the same size. For different-sized groups, use a weighted average.
These examples cover the most common scenarios. For anything more complex, enter your numbers into the calculator above.
Related Calculators
Looking for a different type of calculation? These tools on ezcalcs may help:
- Fraction Calculator for adding, subtracting, multiplying, or dividing fractions.
- Decimal to Fraction Calculator for quick format conversions.
- Discount Calculator for finding sale prices and savings amounts.
- Tip Calculator for splitting bills and calculating gratuity.
Each calculator is free to use with no account required.
Finding What Percent One Number Is of Another
When you need to find what percentage one number is of another, divide the first number by the second, then multiply by 100.
Formula: (Number A ÷ Number B) × 100 = Percentage
Example: What percentage of 60 is 45?
(45 ÷ 60) × 100 = 75%
So 45 is 75% of 60.
This type of percentage calculation shows up constantly:
- Test scores (you got 38 out of 50 questions right: 38 ÷ 50 × 100 = 76%)
- Sales targets (your team closed 17 out of 20 deals: 17 ÷ 20 × 100 = 85%)
- Budget tracking (you spent $340 of a $400 budget: 340 ÷ 400 × 100 = 85%)
Enter both numbers into the calculator above and it handles the math instantly.
Percentage Problems You Can Solve With This Calculator
This percent calculator covers the most common percentage problems:
- What is X% of Y? Find a percentage of a number (tips, discounts, tax amounts).
- X is what percent of Y? Find what percentage one number is of another (test scores, budget usage).
- Percentage change: Calculate percentage increase or percentage decrease between two numbers.
- Percentage difference: Compare two values on equal footing.
- Discount calculations: Enter a price and a percentage to see the discounted amount. For example, a 10% discount off $150 is $15, making the final price $135.
- Markup calculations: Find the percentage markup from cost to selling price.
- Converting fractions and decimals: Turn any fraction or decimal into a percentage instantly.
If your problem involves percentages, type in the numbers and let the calculator do the math.
Percentage Increase and How It Relates to the Original Number
A percentage increase expresses growth relative to the original number. A 50% increase means the new value is 1.5 times the starting point. A 100% increase doubles it.
This matters because the same percentage applied to different original numbers produces different dollar amounts. Adding 10% to 100 gives 10 more. Adding 10% to 1000 gives 100 more. The percentage stays constant, but the absolute increase scales with the base.
Divide by 100, Then Multiply to Get the Result
When you divide a percentage by 100, you convert it to its decimal form. That decimal is the multiplier you need.
- 25% becomes 0.25
- 8% becomes 0.08
- 17.5% becomes 0.175
Multiply the original number by that decimal to find the amount of increase. Then add that amount back to get the final number.
How do I calculate a 10% increase? Multiply the original number by 0.10 to find the increase. Add it to the original, or simply multiply by 1.10. For 75, that gives 75 × 1.10 = 82.50.
How do I add a percentage increase to a number? Use the formula: Original Number × (1 + Percent ÷ 100). This works for any percentage and any starting value.
Percentage Calculator for Any Value
The calculator on this page handles every combination. Enter the base number and the percentage you want to add. It returns both the increase amount and the final value.
Use it for prices, bills, tips, markups, or any scenario where you need to add a percent to a number. Results are estimates for planning. For tax filings, contracts, or regulated pricing, confirm with the relevant authority.
How much is the tip? If your bill is $60 and you want to leave a 20% tip, enter 60 as the number and 20 as the percentage. The calculator shows a $12 tip and a $72 total.
How do I add 30% to a price? Enter the original price and 30. The tool multiplies automatically and shows the final price.
Percentage Math and Algebra Guide
The word "percent" comes from the Latin "per centum," meaning "by the hundred." A percentage is simply a fraction with 100 as the denominator.
- 25% = 25/100 = 0.25
- 8% = 8/100 = 0.08
- 150% = 150/100 = 1.50
Percentages above 100 are valid. Adding 150% to a number more than doubles it, because you keep the original (100%) and add another 150% on top.
In algebra, you can use a variable to represent the unknown. If you know the final number and the percentage but not the original, rearrange the formula:
Original Number = Final Value ÷ (1 + Percentage ÷ 100)
For instance, what number can you add 18 percent to and get 2000? Solve: 2000 ÷ 1.18 = approximately 1694.92.
Learn to Calculate Percent With Related Examples
What is a 50% increase? It means the final value is 1.5 times the original. For 200, a 50% increase gives 300.
How do you increase by 39 percent? Multiply the original number by 1.39. For 100, the result is 139.
How do you add 70 percent to a number? Multiply by 1.70. So 50 × 1.70 = 85.
How do you add 8 percent to a number? Multiply by 1.08. For $25, that gives $27.00.
How do I add two percentages? If both percentages apply to the same base, add them first, then calculate once. Adding 10% and 5% to 200 is the same as adding 15%: 200 × 1.15 = 230. If the second percentage applies to an already increased number (compounding), calculate each step separately.
How do you calculate percentage increase over time? Use the formula for each period: New Value = Previous Value × (1 + Rate). Repeat for each time period. This is compound growth and produces a larger total than a single flat increase.
Where is percentage increase useful? Pricing, salary raises, investment returns, population growth, inflation adjustments, and any context where you compare a new value to an original number.