How to Use Percentage Calculator
Select Mode
Choose percentage of, increase, decrease, or percentage change.
Enter Values
Add the percentage, original value, part, whole, or new value.
Get Answer
See result, formula, explanation, and visual breakdown.
Percentage Formulas
X% of Y = (X ÷ 100) × Y
X is what % of Y = (X ÷ Y) × 100
Percentage Change = ((New - Old) ÷ Old) × 100
Increase = Original + (Percentage × Original)
Decrease = Original - (Percentage × Original)
Percentage Calculator Guide
Percentage is one of the most useful math concepts in daily life. It is used in discounts, marks, profit, loss, taxes, interest rates, salary hikes, business growth, exam scores, price changes, and investment returns. A percentage simply means a value out of 100.
This percentage calculator supports the most common percentage calculations in one place. You can calculate what is X% of Y, find what percentage one number is of another number, increase or decrease a value by a percentage, and calculate percentage change between old and new values.
Percentage of a number
This is used when you want to find a part of a value. For example, 18% GST on a price, 20% discount on a product, or 30% marks weightage in an exam.
Percentage increase and decrease
Percentage increase is used for salary hikes, price growth, revenue growth, and investment growth. Percentage decrease is used for discounts, depreciation, loss, and reduction.
Percentage change
Percentage change compares an old value with a new value. It tells how much the value increased or decreased relative to the original value.
Percentage Calculator FAQs
1. What is a percentage calculator?
A percentage calculator is an online tool that calculates percentage of a number, percentage increase, percentage decrease, percentage change, and reverse percentage.
2. What does percentage mean?
Percentage means per hundred. For example, 25% means 25 out of every 100.
3. How do I calculate X percent of Y?
Use the formula: Result = (X ÷ 100) × Y. For example, 20% of 500 is 100.
4. How do I calculate what percent X is of Y?
Use the formula: Percentage = (X ÷ Y) × 100. For example, 50 is 25% of 200.
5. How do I calculate percentage increase?
Percentage increase can be calculated as New Value = Original Value + (Percentage ÷ 100 × Original Value).
6. How do I calculate percentage decrease?
Percentage decrease can be calculated as New Value = Original Value - (Percentage ÷ 100 × Original Value).
7. How do I calculate percentage change?
Use the formula: Percentage Change = ((New Value - Original Value) ÷ Original Value) × 100.
8. What is reverse percentage?
Reverse percentage means finding the original amount before a percentage increase or decrease was applied.
9. How is discount percentage calculated?
Discount percentage is calculated as Discount Amount ÷ Original Price × 100.
10. How is profit percentage calculated?
Profit percentage is calculated as Profit ÷ Cost Price × 100.
11. How is loss percentage calculated?
Loss percentage is calculated as Loss ÷ Cost Price × 100.
12. How do I calculate marks percentage?
Marks percentage is calculated as Obtained Marks ÷ Total Marks × 100.
13. What is 10% of 1000?
10% of 1000 is 100 because 10 ÷ 100 × 1000 = 100.
14. What is 20% increase on 500?
20% increase on 500 is 600 because 20% of 500 is 100 and 500 + 100 = 600.
15. What is 20% decrease on 500?
20% decrease on 500 is 400 because 20% of 500 is 100 and 500 - 100 = 400.
16. Can this calculator be used for business?
Yes. It can be used for discounts, margins, profit, loss, price change, growth, tax estimates, and sales analysis.
17. Can students use this calculator?
Yes. Students can use it for marks percentage, exam percentage, percentage change, and basic math practice.
18. Is percentage difference the same as percentage change?
No. Percentage change compares old and new value. Percentage difference usually compares the difference relative to the average of two values.
19. Does HQCalc store my values?
No. Calculations happen in your browser and HQCalc does not store your input values.
20. Is this percentage calculator free?
Yes. HQCalc percentage calculator is free to use online.