Percentage Change Calculator
Find the percent increase or decrease from an original value to a new value.
Enter an original value and a new value to see the percent change.
How to use the percentage change calculator
Enter the original value and the new value. The percent change appears right away. A rise shows as a positive percent, a fall as a negative one, and you also see the plain change in absolute terms.
This tool has a direction: it matters which value came first. When neither value is a baseline and you just want the gap between two figures, the percentage difference calculator is the better fit.
How percent change is worked out
Subtract the original value from the new value, divide by the original, and multiply by 100. So going from 80 to 100 is a 25 percent increase, and going from 100 to 80 is a 20 percent decrease. The two are not the same percent, because the starting point differs.
That asymmetry trips people up. A price that rises 25 percent and then falls 25 percent does not return to where it started. For a single percentage of a number, like 20 percent of 150, the percentage calculator handles that directly.
Increase versus decrease
The sign tells you the direction. A positive result is growth, a negative result is a drop. The tool labels it as an increase or a decrease and shows the figure with a sign, so there is no guessing which way the value moved.
The original value cannot be zero, since dividing by zero has no answer. If you enter a zero start, the tool asks for a non-zero value rather than showing an error. To spread a change across several years instead, the CAGR calculator gives an annual rate.
Where percent change helps
Shoppers check how much a price moved during a sale. Investors track a stock from one day to the next. Analysts report quarter-over-quarter changes in revenue or traffic. Any time one number becomes another, this shows the size of the move.
It is also a fast classroom and spreadsheet check. Read the percent, read the absolute change, and you have both views at once. To average several figures while giving some more weight, the weighted average calculator covers that.
Frequently asked questions
- How do I calculate percentage change?
- Subtract the original value from the new value, divide by the original, and multiply by 100. For example, 80 to 100 is (100 - 80) / 80 times 100, which is a 25 percent increase.
- Why is a rise and fall between the same numbers not equal?
- The percent is measured against the starting value, which differs each way. From 80 to 100 is a 25 percent rise, but 100 to 80 is a 20 percent fall, since the bases are 80 and 100.
- What does a negative result mean?
- A negative percent means the value went down. The tool labels it as a decrease and shows the figure with a minus sign, so the direction is clear.
- Can the original value be zero?
- No. Percent change divides by the original value, and dividing by zero has no answer. Enter a non-zero starting value and the tool will show the change.
- How is this different from percentage difference?
- Percent change has a direction and a baseline, the original value. Percentage difference is symmetric and compares two values against their average, with no before or after.