The 3 formulas
- X% of N: (X/100) x N — e.g. 15% of 200 = 30
- Change %: ((New-Old)/Old) x 100 — e.g. 50 to 75 = 50% up
- Reverse: N = Result / (1 + X/100) — e.g. find MRP from sale price
Everyday examples
- Exam: 42/50 = 84%
- Salary hike: Rs.40k to Rs.46k = 15% raise
- Sale: Rs.999 at 25% off = Rs.749.25
Related tools
- Percentage Calculator — all % modes.
- Discount Calculator — sale prices.
- GST Calculator — tax percentages.
Frequently Asked Questions
How do I find X% of a number?
(X / 100) x Number. Example: 15% of 200 = 0.15 x 200 = 30.
How do I find percentage increase?
((New - Old) / Old) x 100. Example: 50 to 75 = (25/50) x 100 = 50% increase.
How do I find percentage decrease?
Same formula — result is negative when the value drops. A 20% discount on Rs.500 = Rs.100 off.
What is percentage difference?
Difference relative to the average of two values. Useful for comparing prices or scores.
Can I do this without a calculator?
Yes for rough math, but the free tool avoids errors — especially with decimals.