Percentage Change Calculator
Enter the old value and the new value.
How this calculator works
Percentage change = (new value – old value) / |old value| x 100. A positive result is an increase and a negative result is a decrease. A drop of 20% followed by a rise of 20% does not return to the start, because each percent uses a different base.
Frequently asked questions
How do I calculate a percent increase?
Subtract the old value from the new one, divide by the old value, and multiply by 100.
Why can I not use zero as the old value?
Dividing by zero is undefined, so there is no percentage change from zero.
Is a 50% decrease the opposite of a 50% increase?
No. A 50% decrease needs a 100% increase to get back to the start.
