Calculator · Pricing & Margin
Percentage Change Calculator: Increase, Decrease and Points
Calculate the percentage increase or decrease between two values, the plain difference, and — when both values are percentages such as margins — the change in percentage points.
Formula and cost boundary
Percentage change = (New value − Starting value) ÷ |Starting value| × 100
Percentage change always compares the difference with the starting value. Enter the earlier figure first: sales last month and this month, a supplier price before and after an increase, a margin before and after a repricing. The starting value cannot be zero, because there is nothing to compare the change with. For a negative starting value — a loss that turned into a smaller loss or a profit — the change is measured against its absolute size, and the share line is not shown because it would mislead.
Worked examples
| Starting value | New value | Difference | Percentage change |
|---|---|---|---|
| 120 orders | 150 orders | +30 | +25.00% |
| $40 supplier price | $34 | −$6 | −15.00% |
| 12.5% margin | 15% margin | +2.5 percentage points | +20.00% |
Percent vs percentage points
When the two values are themselves percentages, two different statements are both true. A margin going from 12.5% to 15% has risen by 2.5 percentage points, the plain difference, and by 20 percent of its starting level, the relative change. Reports often blur the two; say "points" for the difference and "percent" for the relative change, and the reader will know which one you mean.
Successive changes do not add up either. A price cut by 20% and later raised by 20% ends at 96% of where it started: 100 → 80 → 96. To get back from 80 to 100 you need a 25% increase, because the base is smaller after the cut. The same asymmetry explains why a discount needs a larger percentage rise in volume to break even.
How do I calculate a percentage increase?
Subtract the old value from the new one, divide by the old value and multiply by 100. (150 − 120) ÷ 120 = 25%.
What is the difference between percentage change and percentage difference?
Percentage change has a direction and uses the starting value as the base. Percentage difference compares two values with no before and after, usually against their average.
Why can a decrease never be more than 100%?
For a positive value, falling to zero is a 100% decrease; there is nothing further to lose unless the value turns negative.
Method reference: UVM Extension: Markup and Margins. Checked October 26, 2026. Example values are hypothetical.
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