Percentage Calculator Online
A free online percentage calculator for everyday questions: what is X% of Y, what percentage X is of Y (such as marks out of 500), percentage increase or decrease, and adding or subtracting a percentage. Pick a calculator, type two numbers, and the answer and working update as you go.
Calculate the percentage increase or decrease
What is X% of Y?
X is what % of Y?
Add X% to Y
Subtract X% from Y
All calculators
- Percentage increase and decrease calculatorEnter a starting value and a new value to see the percentage change between them. A positive answer is an increase and a negative answer is a decrease.
- What is X% of Y?Enter a percentage and a number to find that percentage of it. For example, 15% of 200 is 30.
- What percent is X out of Y?Enter a part and a whole to see what percentage the part is of the whole, such as marks out of 500 or 600. For example, 394 out of 500 is 78.8%, and 30 is 24% of 125.
- Add a percentage to a numberEnter a number and a percentage to add that percentage on. For example, 120 plus 20% is 144.
- Subtract a percentage from a numberEnter a number and a percentage to take that percentage off it. For example, 120 minus 17.5% is 99.
How to use this page
Pick the calculator that matches your question, enter two values (or a percentage and an amount), and read the result straight away. Each calculator has its own page with the formula, worked examples and common questions.
Example, tax on a purchase: a laptop costs £349.99 before tax and the rate is 12%. Open Add X% to Y, enter 349.99 and 12. The total is £391.99 (391.9888 before rounding to pence).
For only the tax amount, not the total, use What is X% of Y? with the same numbers.
Percentages explained
Percentage increase or decrease
What is the percentage increase from 16 to 25?
((25 − 16) ÷ 16) × 100 = 56.25%
Frequently asked questions
Which calculator should I use for sales tax on a price?
Use Add X% to Y with your pre-tax amount as Y and the tax rate as X to get the total. Use What is X% of Y? if you only need the tax amount.
How do I calculate percentage increase or decrease between two numbers?
Use the percentage increase or decrease calculator: enter the original value first, then the new value. The formula is ((new − old) ÷ |old|) × 100.
How do I find what 15% of 200 is?
Use What is X% of Y? with X = 15 and Y = 200. The result is (15 ÷ 100) × 200 = 30.
How do I calculate a percent discount off a price?
Use Subtract X% from Y, with the original price as Y and the discount as X. That gives the price after the discount.
How do I work out what percentage one number is of another?
Divide the first number by the second and multiply by 100. 394 out of 500 is 394 ÷ 500 × 100 = 78.8%. The X is what % of Y? calculator does this for you.
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. 20% of 30.53 is 0.2 × 30.53 = 6.106. Use What is X% of Y? for any percentage and number.
Is this site free?
Yes. All the calculators are free.
Do I need an account?
No. Nothing here needs you to sign up.
Can I bookmark or share a single calculator?
Yes. Each calculator has its own page in the menu, such as percentage change or percentage of a number. Bookmark or share that page's address.
A brief history of percentages
Percentages are everywhere in daily life: discounts, tax rates, interest, test scores and statistics. Expressing a number “per hundred” makes comparisons across different scales easy. A 5% rise means the same proportional idea whether you're talking about money, population or points on a test.
Antiquity and commerce. Roman finance used hundredths-style levies, for example a 1/100 charge on auction sales (centesima rerum venalium) under Augustus. Thinking in parts of a hundred was already a practical way to standardise fees and shares.
Medieval and early modern Europe. As trade and banking grew, denominators of 100 became routine in arithmetic texts. By the late 15th and early 16th centuries, printed works used them for profit and loss, partnerships and interest. By the 17th century, quoting rates in hundredths was familiar to merchants and lenders.
Why “percent”? The word comes from the Latin per centum, “by the hundred”. Related forms appeared in Italian and other languages before settling into the modern % sign, a compact reminder that percentages are always anchored to one hundred.
Where “percent” means something slightly different
In many sports leagues, a team's record is reported as a decimal such as .500, meaning half of games won. Fans often call that a “winning percentage”, but the number is really a proportion (wins ÷ games played), not a value out of 100. A .500 record means 50% of games won, not 0.5%.
Road gradient signs, such as 12%, describe slope: vertical rise per horizontal distance, scaled so that 100% would mean a 45° angle. That's geometry rather than a “percent of a whole” like a tax rate, but it reuses the same per-hundred language.