Percentage Calculator
Five percentage calculators in one: X% of Y, percent change, reverse percentage and more.
Runs in your browser. Nothing is uploaded.Percentage Calculator in 3 steps
Pick a calculation type
Choose from 5 common percentage questions.
Fill in the numbers
Fields adjust automatically to match what the selected calculation needs.
Get your answer
Click Calculate for an instant, clearly labeled result.
Why use this Percentage Calculator
Questions about this tool
What is "reverse percentage" used for?
It answers questions like "$45 is 15% of what number?" — useful when you know a discounted price and the discount percentage, and need to find the original price.
How is percent increase/decrease calculated?
It uses the formula (new − old) / old × 100. A positive result means an increase, a negative result means a decrease — the sign is shown clearly in the answer.
What does "Add or subtract Z% to/from X" do differently from percent change?
This mode goes the other direction: instead of comparing two numbers to find a percentage, it takes one number and a percentage and calculates the resulting new value — e.g. "add 20% to 150".
Can I use decimal percentages, like 12.5%?
Yes, every field accepts decimal values for precise calculations.
Why the starting number matters
A price rising from ₹80 to ₹100 increases by ₹20. Divide that change by the starting ₹80 and the result is a 25% increase. If the price then falls from ₹100 back to ₹80, divide the ₹20 fall by the new starting point of ₹100: that is a 20% decrease. A 25% rise and a 25% fall do not cancel each other out.
Use “% increase / decrease from X to Y” for the comparison. Use “X% of Y” when you want an amount, such as 18% of ₹2,000 = ₹360. For a discount, decide whether you want the discount amount or the final price: a 10% discount on ₹500 is ₹50, leaving ₹450. If the starting value is zero, a normal percentage-change calculation is undefined; choose another way to describe that change.