Percent Change Calculator

How to use the percent change calculator

Enter the original (starting) value in the first field and the new (ending) value in the second field. The calculator shows the percent change between the two numbers — with a plus sign for an increase and a minus sign for a decrease — along with the direction label and a plain-English summary sentence. The result updates live as you type. Both fields accept decimals, so you can compare values like 1.732 and 2.041 as easily as whole numbers.

How the percent change calculator works

The formula is: Percent Change = ((New Value − Original Value) ÷ Original Value) × 100. For a price that dropped from $120 to $90: (($90 − $120) ÷ $120) × 100 = (−30 ÷ 120) × 100 = −25%. That is a 25% decrease. The negative sign indicates the value went down. For an increase from $90 to $120: (30 ÷ 90) × 100 = +33.3% — note that a 25% decrease is not reversed by a 25% increase. The asymmetry is because the denominator (starting value) is different in each direction.

When to use this calculator

Percent change is the standard way to communicate movement in financial and business data. Use it to measure portfolio performance from one period to the next; to compare monthly, quarterly, or annual revenue and expense figures in business reports; to track how much a stock, bond, or cryptocurrency has moved; to analyze price inflation by comparing current prices to past prices; to evaluate test score improvements between exam attempts; or to compare any two measurements where one is clearly the “before” reference and the other is the “after” result.

Frequently asked questions