About the Percentage Change Calculator
This percentage change calculator tells you by how much a value rose or fell in relative terms. Enter the original (old) value and the new value, and it returns the percent increase or decrease, the absolute difference, the growth multiple (new ÷ old) and the percentage you would need to get back to where you started.
Use it for price rises and discounts, salary changes, sales and traffic growth, stock and portfolio moves, weight change, population change or any before-and-after comparison. If you are comparing two values where neither is the "starting" one, the percentage difference calculator is the better fit.
Percentage change is always measured against the old value. That is why a rise and a fall of the same amount give different percentages, and why recovering from a loss takes a larger percentage gain than the loss itself.
With the default inputs, the percentage change is 25%. Change any value above to recalculate instantly.
How to use the percentage change calculator
- 1Enter the original value in the Old field.
- 2Enter the latest value in the New field.
- 3Read the percentage change — positive is an increase, negative a decrease.
- 4Check the reverse change to see what it would take to return to the original.
Formula and method
Subtract the old value from the new value to get the absolute change, divide by the old value to express it as a fraction of the starting point, and multiply by 100. A positive result is an increase and a negative result is a decrease. Dividing by the absolute value of the old number keeps the sign correct when the starting value is negative.
The growth multiple is simply new ÷ old (1.25 means 25% bigger). The reverse change uses the new value as the base: (Old − New) ÷ |New| × 100, which shows why a 20% drop needs a 25% rise to recover.
- Old
- Starting or original value (must not be 0)
- New
- Final or current value
Worked examples
Price rose from $80 to $100
The price went up by $20. Dividing by the original $80 gives 0.25, a 25% increase. To fall back from $100 to $80 is a 20% decrease, because that drop is measured against the larger $100.
Monthly visitors fell from 12,500 to 9,800
Visitors dropped by 2,700. 2,700 ÷ 12,500 = 0.216, a 21.6% decrease. Getting back to 12,500 from 9,800 would take a 27.55% increase.
Salary from $52,000 to $55,640
The raise is $3,640. Divided by the old salary of $52,000 it is 0.07, a 7% pay increase.
Frequently asked questions
How do you calculate percentage change?+
Subtract the old value from the new value, divide the result by the old value, then multiply by 100. For 40 to 50: (50 − 40) ÷ 40 × 100 = 25% increase.
What is the difference between percentage change and percentage difference?+
Percentage change has a clear before and after and divides by the old value. Percentage difference compares two values with no direction and divides by their average, so it is symmetric.
Can percentage change be more than 100%?+
Yes. Any value that more than doubles has a change above 100% — going from 50 to 150 is a 200% increase. A decrease, however, cannot go below −100% unless the value turns negative.
Why is a 50% drop not reversed by a 50% rise?+
The percentages apply to different bases. 100 falling 50% becomes 50, and 50 rising 50% is only 75. To get back to 100 from 50 you need a 100% increase.
What if the old value is zero?+
Percentage change from zero is undefined because you cannot divide by zero. Report the absolute change instead (for example "up from 0 to 250 units"), or measure from a later, non-zero starting period.