What is the Percentage Calculator?
Percentages express a number as a fraction of 100 and appear everywhere — discounts, exam marks, interest rates, GST, tips, and statistics. This calculator covers the three problems people search for most: finding X% of a number, working out what percent one number is of another, and measuring the percentage increase or decrease between two values.
Each mode shows the result instantly as you type, so you can use it for quick mental-math checks, shopping discounts, mark percentages, or business growth figures.
Percentage Calculator Formula & How It Works
- Percent of: 20% of 150 = 30
- What percent: 30 of 150 = 20%
- Change: 150 → 180 = +20%
All three operations are rearrangements of the same relationship: part = percent × whole. For percentage change, the denominator is always the ORIGINAL value — a price going from ₹100 to ₹150 is a 50% increase, but going back from ₹150 to ₹100 is only a 33.3% decrease.
Worked Examples
Discount: 35% off ₹2,499
35% of 2,499 = (35/100) × 2,499 = ₹874.65 off, so you pay ₹1,624.35.
Exam score: 432 out of 500
(432 / 500) × 100 = 86.4%.
Salary growth: ₹6.5 LPA to ₹8 LPA
((8 − 6.5) / 6.5) × 100 = 23.08% increase.