Percentage Calculator

To find X% of Y, multiply Y by X and divide by 100. For example, 20% of 150 = 150 × 20 ÷ 100 = 30.

Divide the part by the whole and multiply by 100. For example, to find what percent 30 is of 150: (30 ÷ 150) × 100 = 20%.

Subtract the old value from the new value, divide by the absolute value of the old value, and multiply by 100. For example, from 100 to 125: ((125 - 100) ÷ 100) × 100 = 25% increase.

A percentage increase means the new value is larger than the original (positive change), while a percentage decrease means it's smaller (negative change). The formula is the same; the sign of the result tells you the direction.

Yes. A percentage over 100% simply means the value is more than the whole. For example, 200% of 50 equals 100 — the result is twice the original number.

Division by zero is undefined in mathematics. If the base number (whole) is zero, the percentage cannot be calculated. Our calculator will show an error message in this case.

Use the percentage change formula: ((New Value - Old Value) ÷ |Old Value|) × 100. A positive result indicates an increase, and a negative result indicates a decrease.

Divide the known value by the percentage (as a decimal). So 30 ÷ 0.20 = 150. This means 30 is 20% of 150.

Yes — simply move the decimal point one place to the left. For example, 10% of 250 is 25.0. You can then use this to quickly find other percentages: 5% is half of 10%, 20% is double, etc.

To add X%, multiply the number by (1 + X/100). To subtract X%, multiply by (1 - X/100). For example, 150 + 20% = 150 × 1.20 = 180. And 150 - 20% = 150 × 0.80 = 120.