Percentage Change Calculator

Calculate how much a value increased or decreased relative to its starting value. Enter the original value and new value to see whether the change is an increase or decrease, the percent size of that move, and the absolute change in the same units as your inputs.

How to use this calculator

1. Enter the original value, which is the baseline or starting number.
2. Enter the new value, which is the later or comparison number.
3. Review the result label, the percentage magnitude, and the absolute change shown below the main answer.

Use this tool for prices, revenue, measurements, scores, inventory, or any metric with a clear before and after. If neither number is the baseline, compare them with the percentage difference calculator instead.

Formula

$percentage\ change = (new\ value - old\ value) \div old\ value \times 100$

A positive result is an increase. A negative result is a decrease.

Example

If a value rises from 80 to 100:

$(100 - 80) \div 80 \times 100 = 25\%$

If it falls from 100 to 80:

$(80 - 100) \div 100 \times 100 = -20\%$

These are not the same size because the starting values are different.

When percentage change is the right metric

Percentage change answers a directional question: how much did the new value move compared with the original? For finding a new amount after adding a known percent, use the percentage increase calculator. For sale markdowns, the percent off calculator focuses on final price and savings.

Common mistakes

• Dividing by the new value instead of the old value.
• Ignoring the sign of the result.
• Calculating percentage change when the old value is zero.
• Assuming a decrease and later equal increase cancel out.