Percentage Calculator
This percentage calculator helps you quickly answer everyday questions like
“What is 15% of 120?”, “40 is what percent of 200?”, or
“What is the percentage change from 75 to 90?”.
Enter your values, choose the mode, and the tool does the math instantly.
How to use the Percentage Calculator
- Select the desired Mode from the dropdown:
- What is X% of Y?
- X is what percent of Y?
- Percentage change from X to Y
- Type your numbers into the Value X and Value Y fields.
- Click the Calculate button.
- Read the answer in the Result area under the form.
Explanation of the different modes
1. What is X% of Y?
Use this mode when you want to find a part of a whole.
For example, if you want to know What is 20% of 250? enter:
- Mode: What is X% of Y?
- Value X: 20
- Value Y: 250
The calculator multiplies Y by X and divides by 100:
(X / 100) × Y.
In this example, 20% of 250 is 50.
This option is useful for:
- Calculating discounts on shopping receipts.
- Finding tax or tip on a bill.
- Working out commissions, bonuses, or interest.
2. X is what percent of Y?
Choose this mode to see how large one number is compared to another.
For example, if you want to know 30 is what percent of 120? enter:
- Mode: X is what percent of Y?
- Value X: 30
- Value Y: 120
The calculator divides X by Y and multiplies by 100:
(X ÷ Y) × 100.
In this case, 30 is 25% of 120.
This is ideal for:
- Checking exam or quiz scores.
- Comparing performance, such as sales or visitors.
- Understanding how much one value contributes to a total.
3. Percentage change from X to Y
Use this mode to measure how much a value has increased or decreased over time.
For example, to find the percentage change from 80 to 100, enter:
- Mode: Percentage change from X to Y
- Value X: 80 (old value)
- Value Y: 100 (new value)
The calculator uses the formula:
((Y − X) ÷ |X|) × 100.
In this example, the change is +25%, because the value went up from 80 to 100.
This option is helpful for:
- Tracking price increases and discounts.
- Measuring growth in revenue, traffic, or followers.
- Comparing before-and-after results in experiments or projects.
Practical examples
Shopping and discounts
Imagine a jacket costs 90 and there is a 15% discount.
Select What is X% of Y?, enter X = 15 and Y = 90.
The calculator shows 13.5, which is the discount amount.
Subtract 13.5 from 90 to get the final price: 76.5.
Tips and service charges
If a restaurant bill is 48 and you want to leave a 12% tip,
use What is X% of Y? with X = 12 and Y = 48.
The result is 5.76, so a fair total to pay would be 53.76.
Performance and growth
Suppose your website had 2,000 visitors last month and 2,600 this month.
Choose Percentage change from X to Y with X = 2000 and Y = 2600.
The result is +30%, meaning your traffic grew by thirty percent.
Why use an online percentage calculator?
- Fast: Get accurate results in a few seconds.
- Error-free: Avoid common mistakes when calculating by hand.
- Flexible: One tool for percent values, comparisons, and changes.
- Accessible: Works on desktop, tablet, and mobile devices.
Frequently asked questions
What is a percentage?
A percentage is a way to express a number as a fraction of 100.
For example, 25% means 25 out of 100, or one quarter of the whole.
Can I use decimals?
Yes. You can enter whole numbers or decimal values in both fields.
The calculator will handle values like 12.5 or 0.75 without any problem.
What happens if I leave a field empty?
For accurate results, both Value X and Value Y should be filled in.
If a field is missing or contains invalid characters, the calculator will not be able to
complete the operation.
Can this percentage calculator handle negative numbers?
Yes. Negative numbers are useful when you work with losses or drops.
For example, if your value decreases from 50 to 30, the percentage change will be negative,
showing a decrease of 40%.
Is this tool suitable for school and work?
Absolutely. Students can use the percentage calculator for homework and exams,
while professionals can use it for budgeting, reporting, and everyday business decisions.
Whether you are shopping, planning your finances, or analyzing data, this online
percentage calculator gives you clear answers to your percentage questions with just a few clicks.