Percentage Change Calculator

The Difference field shows the absolute gap between the old and new value, while Percentage change shows the size of that gap relative to the old value. A positive result means an increase, a negative result means a decrease.

Percentage change = ((New value − Old value) ÷ Old value) × 100.

• The old value is subtracted from the new value to find the difference.
• The difference is divided by the old value.
• The result is multiplied by 100 to convert it into a percentage change.

Going from 120 to 150 is a 25% increase, calculated as ((150-120) ÷ 120) × 100.

• The old value cannot be zero; division becomes undefined.
• If the new value is smaller than the old value, the result is negative and represents a decrease.

Percentage change calculation is used to find the proportional size of an increase or decrease between two values. The tool on this page instantly calculates the difference and percentage change from the old and new values you enter.

The logic works like this: the old value is subtracted from the new value, the difference is divided by the old value, and the result is multiplied by 100 to convert it into a percentage. For example, going from 120 to 150: (150-120) ÷ 120 = 0.25, and 0.25 × 100 = 25%.

This type of calculation is commonly used to evaluate price increases, salary raises, sales or revenue changes, population growth, and similar comparative figures.

When the new value is smaller than the old value, the result is negative, representing a decrease, drop, or loss — the same logic applies in either direction.

This tool provides only a mathematical calculation. For financial planning or investment decisions, consult official sources or a qualified professional.