Business
Find the percentage increase or decrease between two values.
Enter your numbers to see the answer.
Percentage change calculator guide
Percentage change expresses how much a value has risen or fallen relative to where it started, which makes a $20 rise on $80 and a $200 rise on $800 the same 25% move. This calculator takes an original value and a new value, subtracts one from the other, divides by the size of the original, and reports the result with a plus or minus sign so an increase and a decrease are never confused. It also shows the plain difference between the two numbers. Use it for price rises, salary offers, a change in monthly visitors, a shrinking bill, or any before-and-after comparison where the direction matters. The calculation is symmetric in the sense that it always divides by the original, so a 25% rise is not undone by a 25% fall. Nothing else is applied: no rounding beyond one decimal place in the headline figure, no currency conversion, and no adjustment for inflation between the two dates.
Percentage change (%) = (new value − original value) ÷ |original value| × 100. Difference = new value − original value. A positive result is an increase; a negative result is a decrease.
Worked example with the default inputs: an original value of 80 and a new value of 100. Difference = 100 − 80 = 20. Divide by the original: 20 ÷ 80 = 0.25. Convert to a percentage: 0.25 × 100 = +25%. The calculator shows +25% with the difference of 20 and the new value of 100 beneath it. Reverse the inputs and the answer changes: going from 100 back to 80 is (80 − 100) ÷ 100 × 100 = −20%, not −25%, because the base is now the larger number.
The two values can be in any unit as long as they match: dollars and dollars, kilograms and kilograms, visitors and visitors. The result is a pure percentage and carries no unit. If the two numbers are already percentages, such as an interest rate moving from 4% to 5%, the result is a 25% relative change, whereas the change in percentage points is 1; decide which one you mean before quoting it.
The result is a planning figure that depends entirely on the assumptions you entered. Fees, taxes, payment timing, and rate changes are not captured unless you built them into the inputs, and small errors in a rate compound quickly over time. Verify the rates and terms against your own agreements or your accountant before making a commitment. On this page the figure rests entirely on original value and new value, so start there if the percentage change calculator returns something you did not expect.
Good to know: the order of the fields matters, since the original value is always the divisor. Swapping them turns a 25% rise into a 20% fall. Percentage change and percentage points are not interchangeable: a rate moving from 10% to 12% is a change of 2 points but a 20% relative increase. An original value of zero has no percentage change, and the calculator returns zero rather than infinity.
Use the result for planning, then confirm taxes, fees, contract terms, and other business-specific assumptions. This is not accounting, tax, or investment advice.
How it works
Find the percentage increase or decrease between two values. This tool explains the calculation so you can adjust the assumptions to match your situation.
Worked example
With Original value = 80 · New value = 100 → +25 % (percentage change). Change an input above and this example updates with your numbers.
Common questions
Subtract the original value from the new value, divide by the original value, and multiply by 100. From 80 to 100 that is (100 − 80) ÷ 80 × 100 = 25%. Keep the sign: a negative answer means the value fell.
It is a 25% increase. The difference is 20, and 20 ÷ 80 = 0.25. Going the other way, from 100 to 80, is a 20% decrease, because the divisor becomes 100.
Each change is measured against its own starting point. A 25% rise on 80 reaches 100, but a 25% fall from 100 lands on 75, not 80. To get back to the original you need a 20% fall. The larger the change, the bigger this asymmetry.
Percentage points measure the simple difference between two percentages; percentage change measures that difference relative to the original. An unemployment rate moving from 5% to 6% is up 1 percentage point but up 20% in relative terms.
This tool divides by the absolute value of the original so the sign of the answer follows the direction of the move. A loss of −80 improving to −60 shows as +25%. Many analysts consider percentage change undefined across a sign flip, so quote the plain difference in that case.