Percentage Calculatorحاسبة النسبة المئوية
Three common percentage problems, solved instantly.ثلاث مسائل شائعة في النسبة المئوية، تُحل فوراً.
X% of YX% من Y
X is what % of YX كم % من Y
% Increase / Decrease% الزيادة / النقصان
The three percentage formulas explained
شرح معادلات النسبة المئوية الثلاث
A percentage is simply a fraction out of 100, and almost every real-world percentage question reduces to one of three patterns. The first, "X% of Y," answers questions like "what is 20% of 150?" by converting the percent to a decimal and multiplying: (X ÷ 100) × Y. This is the calculation behind discounts, tips, tax additions, and commission — if an item costs 150 and is 20% off, you're removing (20 ÷ 100) × 150 = 30 from the price.
The second pattern, "X is what percent of Y," flips the question around: instead of knowing the percentage, you know two actual numbers and want the relationship between them expressed as a percentage. The formula is (X ÷ Y) × 100. This is useful for grades (35 correct out of 50 questions), market share, or completion rates on a project.
The third pattern measures percentage change between two values: ((Y − X) ÷ |X|) × 100, where X is the starting value and Y is the ending value. A positive result means growth, a negative result means decline. This is the formula behind reported statistics like "sales grew 12%" or "prices fell 8%," and it's worth remembering that percentage changes aren't symmetric — a 50% increase followed by a 50% decrease does not return you to the original number, because the base amount changes between the two steps. Understanding which of these three patterns applies to your situation is usually the hardest part; the arithmetic itself is straightforward once you know which formula to reach for.