Percentage Calculator

To calculate percentage manually, use the formula: (Part ÷ Whole) × 100. For example, to find what percentage 25 is of 100: (25 ÷ 100) × 100 = 25%. For percentage of a number: (Percentage ÷ 100) × Number. For example, 20% of 150 = (20 ÷ 100) × 150 = 30.

The fastest way is using an online percentage calculator like this one! For mental math, memorize common percentages: 10% (move decimal one place), 25% (divide by 4), 50% (divide by 2), 75% (divide by 4 then multiply by 3). For 20% of 80: 10% is 8, so 20% is 16.

Percentage Increase = ((New Value - Original Value) ÷ Original Value) × 100. For example, if a price increased from $50 to $65: ((65 - 50) ÷ 50) × 100 = (15 ÷ 50) × 100 = 30%. The price increased by 30%.

Reverse percentage finds the original value before a percentage change. For increase: Original = Final ÷ (1 + Percentage/100). For decrease: Original = Final ÷ (1 - Percentage/100). Example: A product costs $120 after 20% VAT. Original price = 120 ÷ 1.20 = $100.

Percentages are crucial in business for profit margins, discounts, growth rates, and performance metrics. They provide a standardized way to compare values regardless of scale. For example, a 20% profit margin means $20 profit for every $100 revenue, making it easy to compare businesses of different sizes.

Percentage increase measures growth: (New > Original). Percentage decrease measures reduction: (New < Original). Both use the same formula structure but give positive or negative results. For example, 100 increased to 120 is +20% increase. 100 decreased to 80 is -20% decrease (or 20% decrease).