Calculate percentages instantly — find percentage of a number, percentage change, increase/decrease, tip calculator, discount finder, markup, and reverse percentage. All in one tool.
What is X% of Y?
10%
1/10 = 0.10
20%
1/5 = 0.20
25%
1/4 = 0.25
33.3%
1/3 = 0.333
50%
1/2 = 0.50
66.7%
2/3 = 0.667
75%
3/4 = 0.75
80%
4/5 = 0.80
90%
9/10 = 0.90
100%
1/1 = 1.00
(X / 100) × Y((New - Old) / |Old|) × 100Y × (1 + X/100)Y × (1 - X/100)(X / Y) × 100Result / (1 + X/100)Cost × (1 + Markup/100)(Markup / Selling) × 100Percentages represent a fraction of 100 and are one of the most commonly used mathematical concepts in everyday life. The word comes from the Latin per centum, meaning "by the hundred." Understanding percentages is essential for financial literacy, academic success, and professional work.
Common percentage calculations include: Finding a percentage of a number (e.g., 20% of 500 = 100), percentage change (how much something increased or decreased), what percentage one number is of another (e.g., 25 is what % of 200?), and reverse percentages (finding the original value before a percentage was applied).
In finance, percentages drive interest rates, investment returns, tax calculations, profit margins, and discount pricing. In academics, grades, test scores, and statistical data are expressed as percentages. In business, growth rates, market share, conversion rates, and KPIs all rely on percentage calculations.
The basic percentage formula is: Percentage = (Part / Whole) × 100. For percentage change: Change = ((New - Old) / Old) × 100. For finding a value after percentage increase: New = Original × (1 + Percentage/100).