Best Percentage calculator Online
Percentage Calculator
Find a percent of a number, percentage change, increase, decrease, discount and more. Free, instant and private.
What is a percentage calculator?
A percentage calculator does the math for any "percent of", "what percent" or "how much did it change" question. Pick a mode, type two numbers and read the answer, with the working shown so you can check it.
How do I calculate 20% of a number?
Choose % of number, enter 20 and your number. The tool multiplies the number by 0.20, which is the same as dividing by 5.
How do I find percentage change?
Choose % change, then enter the old and new values. A positive result is an increase and a negative result is a decrease.
How do I work out a discount?
Choose Discount price, enter the original price and the discount percent. You get the sale price and the amount you save.
How do I add tax or a tip?
Choose Add tax / tip, enter the bill and the percent. The result is the total, and the working shows the extra amount.
Percentage formulas for every mode
The calculator shows the formula for the mode you pick. Here they all are in one place.
| Mode | Formula | Example |
|---|---|---|
| % of number | (X / 100) × Y | 20% of 150 = 30 |
| What % | (X / Y) × 100 | 30 is 20% of 150 |
| % change | ((New − Old) / |Old|) × 100 | 80 → 100 = +25% |
| % increase | X + (X × P / 100) | 200 + 15% = 230 |
| % decrease | X − (X × P / 100) | 200 − 15% = 170 |
| Discount price | Price × (1 − D / 100) | 80 at 25% off = 60 |
| Add tax / tip | Price × (1 + T / 100) | 50 + 8% = 54 |
| Find total | X / (P / 100) | 30 is 20% of 150 |
| % difference | |A − B| / ((A + B) / 2) × 100 | 80 vs 100 = 22.22% |
| Before increase | Final / (1 + P / 100) | 230 after +15% = 200 |
Percentage change uses the absolute value of the old number so a move from a negative value still shows the right direction.
Common percentages: fraction and decimal
Memorize these and many percentages can be done in your head.
| Percentage | Fraction | Decimal | Quick trick |
|---|---|---|---|
| 1% | 1/100 | 0.01 | Divide by 100 |
| 5% | 1/20 | 0.05 | Half of 10% |
| 10% | 1/10 | 0.10 | Move the decimal one place left |
| 20% | 1/5 | 0.20 | Divide by 5 |
| 25% | 1/4 | 0.25 | Divide by 4 |
| 50% | 1/2 | 0.50 | Divide by 2 |
| 75% | 3/4 | 0.75 | Three quarters |
| 100% | 1/1 | 1.00 | The whole amount |
| 200% | 2/1 | 2.00 | Double |
Where percentage math shows up
Shopping
Check the real sale price, then compare two offers fairly. 25% off 80 is 60.
Restaurants
Add a 15% or 20% tip to a bill without guessing. 15% of 50 is 7.50.
Salary and raises
See what a 10% raise does to your pay. 50,000 plus 10% is 55,000.
Business
Track growth, margins and month-over-month change in sales or traffic.
Students
Turn a score into a grade. 42 out of 50 is 84%.
Taxes and fees
Add VAT or sales tax to a price, or work backwards to the price before tax.
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Everything you need to calculate percentages
A complete percentage toolkit for students, shoppers, writers and business owners, built to be fast and private.
10 percentage modes in one calculator
From basic percent-of to discounts, tax and reverse percentages, with no switching between tools.
Shows the working
See the numbers plugged into the formula.
Swap values
Flip the two inputs with one click.
Pick your decimals
Auto, or fix the result to 0 to 4 places.
Instant results
No button to press, no signup, no limits.
Private by design
Everything runs in your browser. Your numbers are never uploaded or stored.
Copy result or steps
Copy just the answer, or the answer with its working for homework and reports.
See the calculator in action
Real before-and-after examples show what each mode returns.
Percent of a number
Percentage change
Discount price
Reverse percentage
How the percentage calculator works
Four quick steps from question to answer.
Pick a mode
Choose percent of, change, discount, tax or another mode.
Enter two numbers
Type or paste the values into the two boxes.
Check the working
The result and its formula update as you type.
Copy the answer
Copy the result, or the result with the steps.
Percentage tips by situation
Quick mental shortcuts for everyday percentages. For anything important, run the numbers in the calculator.
Sale prices
Take 10% off by moving the decimal, then build other discounts from it.
30% off 90 = 90 − 27 = 63Tips
Find 10% first, then double it for 20% or add half of it for 15%.
15% of 60 = 6 + 3 = 9Growth rates
Always divide by the starting value, not the ending one.
(New − Old) / Old × 100Test scores
Divide your score by the total marks, then multiply by 100.
42 / 50 × 100 = 84%Tax-inclusive prices
To remove tax from a total, divide by 1 plus the rate. Do not subtract the rate.
108 / 1.08 = 1006 percentage mistakes to avoid
Small slips give wrong answers. Spot them and fix them fast.
Dividing by the new value
Percentage change is measured from the starting value.
Up 50%, down 50%
The second percentage applies to the new, larger base.
Adding discounts
Stacked discounts multiply. They do not add.
Wrong decimal
Divide the percent by 100 before multiplying.
Subtracting tax back
Use the Before increase mode to undo a percentage.
Percent vs percentage points
The gap between two percentages is in points. The relative change is a percent.
Your numbers never leave your browser
Many online tools send what you type to a server. This calculator does not, which makes it safe for salaries, invoices and private figures.
Nothing is uploaded
All math happens on your device using your browser.
Nothing is stored
We do not save, log or read the numbers you type.
Safe for private figures
Use it for pay, budgets, invoices and grades without worry.
Percentage glossary
A plain-English guide to the terms used on this page.
Percent
A number expressed as a part of 100. 45% means 45 out of 100.
Percentage point
The plain gap between two percentages. Going from 4% to 6% is 2 points.
Base value
The number a percentage is measured against, such as the original price.
Percentage change
How much a value moved from its starting point, as a percent of that start.
Markup
A percentage added on top of a cost to set a selling price.
Discount
A percentage taken off a price. It lowers the amount to pay.
Decimal form
A percent divided by 100. 8% is 0.08 and is what you multiply by.
Fraction form
A percent written as a ratio. 25% is one quarter.
Percentage calculator FAQ
Quick answers to the most common questions.
How do I calculate 20% of a number?
Multiply the number by 0.20, or divide it by 5. For example, 20% of 150 is 150 × 0.20 = 30.
How do I calculate percentage increase?
Use ((New − Original) / Original) × 100. For example, from 50 to 65 is ((65 − 50) / 50) × 100 = 30%.
What is the difference between percentage change and percentage difference?
Percentage change has a direction and is measured from an original value. Percentage difference compares two values with no original, dividing by their average, so it is always positive. Use change for before and after, and difference for two equal peers.
How do I calculate a discount?
Discount amount = price × (discount % / 100). Final price = price − discount amount. For example, 30% off 100 is a 30 discount and a final price of 70.
Can a percentage be more than 100%?
Yes. 200% means double the reference amount. Going from 100 to 250 is a 150% increase.
How do I convert a decimal to a percentage?
Multiply the decimal by 100 and add the % sign. 0.75 becomes 75%. To go back, divide the percentage by 100.
How do I find the original price before a percentage increase?
Divide the final value by 1 plus the percentage as a decimal. Use the Before increase mode. For example, 230 after a 15% increase is 230 / 1.15 = 200.
Is my data uploaded or stored?
No. Every calculation runs in your browser. Your numbers are not sent to a server and are not saved.
Ready to calculate?
Pick a mode, type two numbers and get your answer in a second.