Percentage Change Calculator

Percentage change = (new - old) / |old| x 100. A positive result is an increase and a negative one a decrease. The multiple is simply new / old, which is often the clearer way to say it once a change passes 100 percent.

How do I calculate percentage increase?

Subtract the old value from the new one, divide by the old value, and multiply by 100. Going from 80 to 100 is 20 divided by 80, which is 25 percent.

Why does a 50 percent drop need a 100 percent rise to recover?

Because each percentage is measured against a different base. 100 falling by half is 50, and getting from 50 back to 100 means doubling, which is a 100 percent rise. This is why investment losses hurt more than the equivalent gain helps.

What is percentage difference, as opposed to change?

Percentage difference compares two values with no before or after, dividing by their average rather than by the first one. Use change when one number came first, and difference when neither did.