Percentage Calculator

To find what percentage one number is of another, divide the first number by the second number and multiply by 100. For example, to find what percentage 25 is of 100: (25 ÷ 100) × 100 = 25%.

Percentage increase specifically measures growth (always positive), while percentage change can be either positive (increase) or negative (decrease) depending on whether the new value is larger or smaller than the original.

To calculate percentage decrease: ((Original Value - New Value) ÷ Original Value) × 100. For example, if a price drops from $100 to $80: ((100 - 80) ÷ 100) × 100 = 20% decrease.

Yes, you can calculate a percentage of a percentage. For example, 50% of 20% = 0.50 × 0.20 = 0.10 = 10%. This is useful for compound calculations like discounts on already discounted items.

The formula for percentage increase is: ((New Value - Original Value) ÷ Original Value) × 100. This tells you by what percentage the original value has increased.

To convert a decimal to a percentage, multiply by 100 and add the % symbol. For example, 0.25 × 100 = 25%, or 0.075 × 100 = 7.5%.

Common mistakes include: forgetting to multiply by 100, using the wrong base value for the calculation, confusing percentage points with percentages, and mixing up increase vs. decrease formulas.

For compound percentage changes, you can't simply add percentages. Instead, multiply the factors: if something increases 20% then 10%, the total is: 1.20 × 1.10 = 1.32, which is a 32% total increase.

Yes, this calculator uses standard mathematical formulas and provides accurate results suitable for business, academic, and professional use. However, always verify critical calculations independently.

Absolutely! Use the basic percentage calculator to find tips (e.g., 18% of $50) or to calculate taxes. You can also use it to determine how much you saved with a discount.