Percentage Change Calculator

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Percentage Change Calculator

Calculate the percentage increase or decrease between two values and review the formula beside the answer.

Last updated: March 2026 | By ForgeCalc Engineering

Percentage Change Solver

Growth or decline

Calculation Steps

1.Initial value: 100
2.Final value: 120
3.Change = 120 - 100 = 20
4.Formula: (change / absolute initial) × 100
5.Calculation: (20 / 100) × 100 = 20%
Result
20%

Increase

What Is Percentage Change?

Percentage change expresses how much a value increases or decreases relative to its starting point. It is used in finance, science, and business to compare growth and decline.

How to Calculate Percentage Change

  1. Subtract the initial value from the final value.
  2. Divide the result by the absolute value of the initial value.
  3. Multiply by 100.
  4. Read the positive result as increase or the negative result as decrease.
change = ((final - initial) / |initial|) x 100

Worked Example

Example: 100 to 120 is a 20% increase.

(120 - 100) / 100 x 100 = 20%

Frequently Asked Questions

Can percentage change be negative?

Yes. A negative result means the value decreased.

What if the initial value is zero?

The calculation is undefined because you cannot divide by zero.

Is percent change symmetric?

No. The starting value is the reference point.

Does this accept decimals?

Yes. Any finite real numbers are accepted.

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