How to Calculate Percentage: Marks, Discounts and Increase
Updated 18 October 2026 · 4 min read
Easy formulas with examples: percentage of marks, discount price, percentage increase and decrease.
Percentage of marks
Formula: (marks obtained ÷ total marks) × 100.
Example: 432 out of 500 → (432 ÷ 500) × 100 = 86.4%.
Find X% of a number
Formula: (X ÷ 100) × number.
Example: 18% of ₹2,500 → 0.18 × 2,500 = ₹450.
Discount price
Formula: price − (price × discount ÷ 100).
Example: ₹1,999 with 30% off → 1,999 − 599.70 = ₹1,399.30. The Discount Calculator does this instantly.
Percentage increase or decrease
Formula: ((new − old) ÷ old) × 100.
Example: salary from ₹40,000 to ₹46,000 → (6,000 ÷ 40,000) × 100 = 15% increase. A negative answer means a decrease.