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What is X% of Y?
Formula: Result = (X ÷ 100) × Y
X is what % of Y?
Formula: Result = (X ÷ Y) × 100
Percentage Change
Formula: ((New − Old) ÷ Old) × 100
Increase a Value by %
Formula: Value × (1 + Percent ÷ 100)
Decrease a Value by %
Formula: Value × (1 − Percent ÷ 100)
Percentage Difference
Formula: |A − B| ÷ ((A + B) ÷ 2) × 100
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How to Calculate Percentage?
Percentage is a way to express a number as a fraction of 100. The word "percent" comes from the Latin "per centum" meaning "by the hundred."
Basic Percentage Formula
Percentage = (Part ÷ Whole) × 100
Example: If 30 students passed out of 50, the pass percentage = (30 ÷ 50) × 100 = 60%.
Percentage Change Formula
To find how much a value has increased or decreased: % Change = ((New Value − Old Value) ÷ Old Value) × 100. A positive result = increase, negative = decrease.
Uses of Percentage in Daily Life
Percentages are used everywhere — in exam scores, discounts and offers, interest rates on loans, tax calculations, nutrition labels on food, and statistical data in news reports. Understanding percentage calculations is a fundamental life skill.