How do I calculate the percentage change between two numbers?
Enter the starting value in the From field and the ending value in the To field. The tool subtracts, divides by the starting value, and multiplies by 100, then labels the result Increase or Decrease. By hand: (new - old) / old x 100.
Is this percentage change calculator free?
Yes, free with no signup. Both results recompute on every keystroke in your browser, and nothing you type is sent to a server.
Is percentage increase calculated the same way as percentage decrease?
Yes, one formula covers both: the sign of the change decides which label you see. From 50 to 60 gives +20% and reads Increase; from 60 to 50 gives -16.7% and reads Decrease.
Why is 80 to 100 a 25% rise but 100 to 80 only a 20% fall?
Because the base changes. The rise is 20 measured against a base of 80, which is 25%. The fall is the same 20 measured against a base of 100, which is 20%. Percentage changes are never reversible by flipping the sign.
What is the difference between percentage change and percentage points?
A rate moving from 2% to 3% has risen by one percentage point, and it has risen 50% in relative terms. This calculator gives you the relative figure. Both are correct, and reporting the 50% when you mean the one point is how numbers get inflated in a deck.
What does it show when the starting value is zero?
It shows 0%. A change from zero to anything is an infinite percentage increase, which is not a useful answer, so the code guards against the division and returns zero instead. Use the absolute change line in that case.
How does it handle negative numbers?
It divides by the absolute value of the from field. A move from -50 to -25 is a change of +25 against a base of 50, reported as +50%. That is a defensible convention, but check that it matches how your finance team defines it before you quote it.
Can it give an annual growth rate across several years?
No. It compares exactly two values with no time dimension. For a compound annual growth rate you need (end / start)^(1 / years) - 1, which is a different calculation.
What is the difference between percentage change and percent difference?
Percentage change has a direction and a baseline: it measures from the old value to the new one. Percent difference treats the two values as peers and divides the gap by their average, so it is the right measure when neither number is the starting point. This tool computes the change, not the difference.
If something drops 50%, what increase gets it back to the original?
100%, not 50%. A fall from 200 to 100 halves the base, so the return trip is measured against 100 and needs to double it. You can verify both legs here: 200 to 100 reads -50%, and 100 to 200 reads +100%.
Are the numbers I enter sent anywhere?
No. The subtraction and division run in your browser tab, nothing is posted to a server, and the calculator keeps working with the network disconnected.