- Percentage increase $=\dfrac{\mbox{New value}-\mbox{Old value}}{\mbox{Old value}}\times 100\%$
- Percentage decrease $=\dfrac{\mbox{Old value}-\mbox{New value}}{\mbox{Old value}}\times 100\%$
- Percentage change $=\dfrac{\mbox{New value}-\mbox{Old value}}{\mbox{Old value}}\times 100\%$