Percentage Calculator

To find what percentage X is of Y, divide X by Y and multiply by 100. For example, if you want to know what percentage 25 is of 100, calculate: (25 ÷ 100) × 100 = 25%. Our calculator does this instantly for you.

For percentage increase: ((New Value - Original Value) ÷ Original Value) × 100. For percentage decrease: ((Original Value - New Value) ÷ Original Value) × 100. The calculator automatically determines whether it's an increase or decrease and shows the result.

To find X% of a number, multiply the number by X and divide by 100. For example, to find 15% of 200: (200 × 15) ÷ 100 = 30. You can also convert the percentage to a decimal (15% = 0.15) and multiply: 200 × 0.15 = 30.

If you know the final price after a discount, divide it by (1 - discount percentage as decimal). For example, if something costs $80 after a 20% discount, the original price is: $80 ÷ (1 - 0.20) = $80 ÷ 0.80 = $100.

To add X% to a number, multiply by (1 + X/100). To subtract X% from a number, multiply by (1 - X/100). For example, to add 15% to 100: 100 × 1.15 = 115. To subtract 15% from 100: 100 × 0.85 = 85.

Percentage points refer to the arithmetic difference between two percentages. For example, if something increases from 10% to 15%, that's a 5 percentage point increase. Percentage change refers to the relative change: (15-10)/10 × 100 = 50% increase.

For compound increases, multiply by (1 + percentage/100) for each increase. For example, a 10% increase followed by a 20% increase: Original × 1.10 × 1.20 = Original × 1.32, which is a total 32% increase.

Yes! Percentages over 100% are common, especially for increases. For example, if something doubles in value, that's a 100% increase. If it triples, that's a 200% increase. A value that is 150% of the original means 1.5 times the original.