Percentage calculator

The three most common percentage calculations in one place. A percent is one hundredth of a whole:

$X\%\ \text{of}\ Y=\frac{X}{100}\cdot Y$

Percentage share (what % is $X$ of $Y$): $\dfrac{X}{Y}\cdot100\%$. Percentage change is always measured relative to the initial value:

$\frac{B-A}{A}\cdot100\%$

The calculator tells you whether it is an increase or a decrease. Note: a 50% increase followed by a 50% decrease does not return to the starting point — because percentages are taken from different bases.