Percentage calculator

Percentage Change Calculator

Calculate percentage increase or decrease between two values using the standard change formula. Measure price changes, growth rates, salary adjustments, and any metric that changes over time with clear positive or negative results.

Last updated August 24, 2026

Calculate percentage change

Enter the initial value and final value to measure increase or decrease.

How this calculator works

Percentage change measures how much a value has increased or decreased relative to its original amount. It is calculated as ((New Value - Original Value) / Original Value) * 100. The result is positive for increases and negative for decreases. This makes percentage change more flexible than separate increase or decrease calculators because it handles both directions with one formula.

The original value is always the denominator because it is the baseline. Dividing by the original value makes the result independent of scale, so you can compare a 20% increase on $50 with a 20% increase on $5,000 directly. The same dollar increase means very different percentages depending on the starting point. A $10 increase from $50 is 20%, while the same $10 increase from $1,000 is only 1%.

Common use cases include tracking price changes over time, measuring business growth rates, comparing salary adjustments, analyzing website traffic trends, evaluating test score improvements, and monitoring population changes. In finance, percentage change is used for stock returns, revenue growth, and expense tracking. In economics, it measures inflation, GDP growth, and employment changes. In education, it tracks student progress from one test to another. In healthcare, it monitors patient recovery rates or disease spread.

Tips: A positive result means the value increased. A negative result means it decreased. If the new value equals the original value, the percentage change is zero. If the original value is zero, the calculation is undefined because you cannot divide by zero. Watch for the sign: a negative percentage change still represents a valid magnitude. For example, -15% means the value dropped by 15%. For comparing two values without a clear baseline, use Percentage Difference instead.

Also try: Percentage Increase Calculator when you know the result is growth, or Percentage Decrease Calculator when you know the result is a drop.

Methodology

The calculator uses ((New Value - Original Value) / Original Value) * 100. The original value is the baseline. If the original value is zero, the calculation is undefined. A positive result indicates an increase, and a negative result indicates a decrease.

Examples

  • A product price rising from $80 to $100: (100 - 80) / 80 * 100 = 25% increase.
  • A salary falling from $60,000 to $54,000: (54,000 - 60,000) / 60,000 * 100 = -10% decrease.
  • Website traffic growing from 8,000 to 10,000 visits: (10,000 - 8,000) / 8,000 * 100 = 25% increase.
  • A stock price dropping from $50 to $42.50: (42.50 - 50) / 50 * 100 = -15% decrease.
  • Company revenue rising from $2M to $2.4M: (2.4M - 2M) / 2M * 100 = 20% increase.

Common questions

How do I calculate percentage change?

Subtract the original value from the new value, divide by the original value, then multiply by 100. For example, if a price rises from $50 to $65: (65 - 50) / 50 * 100 = 30% increase.

Can percentage change be negative?

Yes. A negative result means the value decreased. For example, if a price falls from $80 to $60: (60 - 80) / 80 * 100 = -25%. The magnitude is 25%, and the sign shows the direction.

What if the original value is zero?

The calculation is undefined because you cannot divide by zero. Percentage change requires a valid original value as the baseline.

What is the difference between percentage change and percentage difference?

Percentage change uses the original value as the baseline. Percentage difference compares two values relative to their average. Use percentage change when one value is clearly the starting point. Use percentage difference when neither value is naturally the baseline.

Why is the original value used as the reference point?

The original value is the baseline. Dividing by it makes the result independent of scale, so you can compare changes across different starting values directly.

How do I find the new value after a percentage change?

Multiply the original value by (1 + percentage / 100). For an increase, add the percentage. For a decrease, subtract it. For example, a 15% increase on $200 gives 200 * 1.15 = $230.