Percentage Formula Explained with Real Examples (2026)

Percentage is one of the most universally useful math concepts. From calculating exam scores and tax amounts to understanding discounts and salary hikes, percentage calculations appear in almost every area of life. This guide explains the core formula and covers the three most common percentage problem types with clear, real-world examples.

What is a Percentage?

A percentage (from Latin "per centum" = "per hundred") is a ratio expressed as a fraction of 100. It is denoted with the % symbol. 50% means 50 out of 100, or simply 0.5 as a decimal.

The 3 Types of Percentage Problems

Type 1: What is X% of Y?
Formula: Answer = X / 100 — Y
Example: What is 20% of 5,000? → 20/100 — 5,000 = 1,000

Type 2: What percent is X of Y?
Formula: % = X Y — 100
Example: 40 marks out of 50 in a test → 40 50 — 100 = 80%

Type 3: X is Y% of what number?
Formula: Whole = X Y — 100
Example: 60 is 25% of what? → 60 25 — 100 = 240

Real-Life Examples

• → Discount: 30% off 2,000 → Discount = 0.30 — 2,000 = 600. Final = 1,400
• Tax: 18% GST on 10,000 → Tax = 0.18 — 10,000 = 1,800. Total = 11,800
• Exam: 78 out of 100 marks → Percentage = 78 100 — 100 = 78%
• Salary Hike: 50,000 with 12% hike → Increase = 0.12 — 50,000 = 6,000. New = 56,000

Use Our Free Percentage Calculator

Also check our Percentage Increase & Decrease Guide for calculating salary hikes, price changes, and more.

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