RSPercentDesk guides
Practical notes for percentage calculator, including examples and the limits of each workflow.
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Understanding the base in percentage change
Percentage change uses the difference between new and old values, divided by the old value, multiplied by 100. A move from 80 to 100 is an increase of 25%.
READ THE GUIDEA discount is not the same as a price change
For a 15% discount on 200, the reduction is 30 and the resulting value is 170. This arithmetic does not include taxes, shipping or other charges unless you include them in your inputs.