Why Percentages Matter
Percentages express a proportion out of 100. They appear everywhere: exam scores, bank interest, discounts, tax rates, salary increments, and data analysis. Despite looking intimidating, all percentage problems fall into one of three patterns.
The Three Methods
Formula: Result = (N × X) / 100
Examples:
20% of ₹1,500 = (1500 × 20) / 100 = ₹300
7.5% of ₹80,000 = (80000 × 7.5) / 100 = ₹6,000
18% GST on ₹10,000 = (10000 × 18) / 100 = ₹1,800
Use for: tax, discount amount, interest, commission.Common Shortcuts
Find 10%
Move the decimal one place left. Example: 10% of 345 = 34.5
Find 1%
Move the decimal two places left. Example: 1% of 4,500 = 45
Find 25%
Divide by 4. Example: 25% of 800 = 200
Find 50%
Divide by 2. Example: 50% of 960 = 480. For 5%, halve the 10% value: 10% of 200 = 20, so 5% = 10.
A Quick Reference Table
| Goal | Formula |
|---|---|
| X% of a number N | (N × X) ÷ 100 |
| A is what % of B? | (A ÷ B) × 100 |
| % increase from A to B | ((B − A) ÷ A) × 100 |
| % decrease from A to B | ((A − B) ÷ A) × 100 |
| Add X% to N | N × (1 + X/100) |
| Remove X% from N | N ÷ (1 + X/100) |
Calculate Percentages Now
Use our free Percentage Calculator for all three methods — type in any two values and get the third instantly. No mental math required.