Percentage Calculator for Marks, Discount and Increase

Guide

The three formulas

X% of Y = Y × X ÷ 100 – for example 18% of ₹2,500 is ₹450. X is what % of Y = X ÷ Y × 100 – for example 437 marks out of 500 is 87.4%. Change from A to B = (B − A) ÷ A × 100 – a price that moves from ₹800 to ₹1,000 has risen 25%, while one that falls from ₹1,000 to ₹800 has dropped 20%. Notice the two answers differ because the starting value changes.

Discounts and sale prices

For a discount, the final price is Price × (1 − discount ÷ 100). Two discounts in a row do not add up: 50% plus an extra 20% off is a total of 60%, not 70%. When a shop shows ‘up to 70% off’, check the actual percentage on the item you want with this tool. On FastBuySale, use it to see how much below the new price a used item is being offered.

Marks and CGPA

For board exams, percentage is total marks obtained ÷ maximum marks × 100. Many universities convert CGPA to percentage by multiplying by 9.5 (CBSE method), but each university can use its own rule – always check your marksheet or university notice before writing a percentage on a job form.

Quick examples

Marks: 437 out of 500 = 87.4%; 612 out of 700 = 87.43%. Discount: a ₹2,499 shirt at 40% off costs ₹1,499.40. Salary hike: ₹30,000 to ₹33,600 is a 12% increase. Price fall: a used phone listed at ₹12,000 that sells for ₹10,800 went for 10% less. Tip: ₹1,840 restaurant bill with 10% tip is ₹2,024. Exam cut-off: needing 33% of 80 marks means at least 26.4, so 27 marks.